Infectious Disease Exam 1

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1. Most common causative agent of the system infection, infective (septic) arthritis?

Explanation

S. aureus is the most common causative agent of infective (septic) arthritis. This bacterium is a common pathogen that can cause a wide range of infections in various parts of the body, including the joints. It is known for its ability to invade and infect the synovial fluid and tissues of the joints, leading to the development of septic arthritis. S. aureus is particularly virulent and can cause severe symptoms and complications if not promptly treated.

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About This Quiz
Microbiology Quizzes & Trivia

Infectious Disease Exam 1 focuses on the characteristics of Staphylococcus saprophyticus, contrasting it with other species like S. Aureus. It assesses knowledge on hemolysis patterns, coagulase, DNase activity, and mannitol fermentation, crucial for medical and microbiological education.

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2. Which causes the systemic infection post-viral lobar pneumonia

Explanation

S. aureus is the correct answer because it is a common cause of systemic infection following lobar pneumonia. This bacterium is often found in the respiratory tract and can cause pneumonia, which can then lead to a systemic infection if it spreads beyond the lungs. S. epidermidis and S. saphrophyticus are not typically associated with causing systemic infections following lobar pneumonia.

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3. Most common causative agent of the systemic infection, bacteremia and sepsis (pyemia)

Explanation

S. aureus is the most common causative agent of systemic infections such as bacteremia and sepsis (pyemia). This bacterium is a common pathogen that can cause a wide range of infections in various parts of the body. It is known for its ability to produce toxins and evade the immune system, leading to severe infections. S. aureus is often found on the skin and nasal passages of healthy individuals but can cause serious infections when it enters the bloodstream or other tissues.

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4. Are Strep Gram positive or negative?

Explanation

Strep bacteria are Gram-positive. This means that they retain the crystal violet stain in the Gram staining process, appearing purple under a microscope. Gram-positive bacteria have a thick peptidoglycan layer in their cell walls, which retains the stain. In contrast, Gram-negative bacteria do not retain the stain and appear pink or red.

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5. Cystitis is

Explanation

Cystitis refers to the inflammation of the bladder, which is commonly caused by a bacterial infection. It typically presents with symptoms such as frequent urination, a strong urge to urinate, and a burning sensation during urination. Cystitis is classified as a lower urinary tract infection (UTI) because it primarily affects the bladder. Upper UTIs, on the other hand, involve the kidneys and are usually more severe. Therefore, the correct answer is lower UTI.

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6. Staphylococcus

Explanation

Staphylococcus is a type of bacteria that is known for its characteristic arrangement in grape-like clusters. This arrangement is due to the bacteria dividing in multiple planes and remaining attached to each other. In contrast, bacteria that form long chains typically belong to the genus Streptococcus. Therefore, the given correct answer of "grape-like clusters" accurately describes the arrangement of Staphylococcus bacteria.

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7. Beta-hemolytic

Explanation

The correct answer is S. aureus because it is the only bacterium listed that is beta-hemolytic. Beta-hemolysis refers to the complete lysis of red blood cells, resulting in a clear zone around bacterial colonies on blood agar plates. S. epidermidis and S. saprophyticus are both coagulase-negative staphylococci and are not known to exhibit beta-hemolysis. Therefore, S. aureus is the most likely bacterium to be beta-hemolytic among the options provided.

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8. Systemic infection of S. aureus due to highly absorbent tampons

Explanation

Toxic shock syndrome is a rare but serious condition caused by a bacterial infection, often associated with the use of highly absorbent tampons. In this case, the systemic infection of S. aureus, a type of bacteria, is the cause of toxic shock syndrome. This condition can lead to symptoms such as high fever, rash, low blood pressure, and organ failure. It is important to seek medical attention immediately if toxic shock syndrome is suspected, as it can be life-threatening.

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9. S. aureus resistant to methicillin (Methicillin Resistant Staph Aureus MRSA) treated with 

Explanation

Vancomycin is the correct answer because it is known to be effective against methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a type of bacteria that has developed resistance to many antibiotics, including methicillin. Vancomycin is often considered the drug of choice for treating MRSA infections due to its effectiveness against this particular strain of bacteria. Penicillin, methicillin, and bacitracin are not effective against MRSA, as they are susceptible to resistance mechanisms developed by the bacteria.

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10. In pustulent or necrotic tissues due to S. aureus infection, what treatment?

Explanation

In cases of pustulent or necrotic tissues caused by a Staphylococcus aureus infection, surgical debridement is the appropriate treatment. Surgical debridement involves the removal of infected or dead tissue to promote healing and prevent the spread of infection. Bacitracin cream or ointment may be used as adjunctive therapy to prevent secondary infection, but they alone would not be sufficient to treat the underlying infection and remove the necrotic tissue. Therefore, surgical debridement is the correct answer.

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11. Yellow-golden colored, round shape

Explanation

The correct answer is S. aureus because it is the only bacterium among the options that is commonly associated with a yellow-golden color and round shape. S. epidermidis and S. saprophyticus do not typically exhibit these characteristics.

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12. S. aureus

Explanation

The given correct answer is "DNase positive". This means that the bacterium Staphylococcus aureus produces the enzyme DNase, which is capable of breaking down DNA. This trait is important in distinguishing S. aureus from other bacteria, as not all bacteria have the ability to produce DNase.

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13. Which is the most common causative agent of the systemic infection, acute bacterial endocarditis?

Explanation

S. aureus is the most common causative agent of acute bacterial endocarditis, a systemic infection. This bacterium is known for its ability to cause a wide range of infections, including endocarditis, which is an infection of the inner lining of the heart. S. aureus is a particularly virulent pathogen, capable of causing severe infections and complications. It is often found in the normal flora of the skin and nasal passages, making it easily accessible to enter the bloodstream and infect the heart valves.

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14. Causes the sytemic infection Staphylococcal Colitis (Necrotizing enterocolitis)

Explanation

S. aureus is the correct answer because it is a known cause of Staphylococcal Colitis, also known as Necrotizing enterocolitis. This infection is characterized by inflammation and necrosis of the intestinal mucosa, which can lead to severe complications. S. epidermidis and S. saprophyticus are not typically associated with this specific infection.

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15. Staph epidermidis is part of normal flora

Explanation

Staph epidermidis is considered part of the normal flora because it is commonly found on the skin and mucous membranes of healthy individuals. It is a commensal bacterium that does not typically cause harm or infection in healthy individuals. This bacterium plays a role in maintaining the balance of the skin microbiome and can provide protection against pathogenic organisms. Therefore, the statement that Staph epidermidis is part of the normal flora is true.

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16. The urease produced by ________ may mediate host pathogenesis.

Explanation

S. saprophyticus may produce urease, which can play a role in causing disease in the host. Urease is an enzyme that breaks down urea into ammonia and carbon dioxide. This can lead to the formation of alkaline conditions in the host's urinary tract, which can be detrimental to the host and contribute to pathogenesis.

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17. S. aureus 

Explanation

Coagulase positive refers to the ability of the bacterium Staphylococcus aureus to produce the enzyme coagulase. Coagulase is responsible for clotting blood plasma, which helps the bacteria evade the immune system by forming a protective barrier around itself. This characteristic is important in distinguishing S. aureus from other staphylococci that are coagulase negative.

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18. Can contaminated food carry S. aureus?

Explanation

Contaminated food can carry S. aureus because this bacterium is commonly found in the nose and skin of healthy individuals. If proper food handling and hygiene practices are not followed, S. aureus can be transferred to food and cause contamination. Consuming contaminated food can lead to food poisoning symptoms such as nausea, vomiting, and diarrhea. Therefore, it is important to ensure that food is properly cooked, stored, and handled to prevent the growth and spread of S. aureus.

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19. Which organism infects both normal and damaged heart valves?

Explanation

S. aureus is the correct answer because it is a type of bacteria that can infect both normal and damaged heart valves. This bacterium is known to cause endocarditis, which is an infection of the inner lining of the heart and heart valves. S. aureus can attach to damaged heart valves and form a biofilm, making it difficult to treat and leading to serious complications. It can also infect normal heart valves, although this is less common.

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20. For dry foot lesions caused by S. aureus, use

Explanation

Bacitracin ointment is the recommended treatment for dry foot lesions caused by S. aureus. Bacitracin is an antibiotic that works by stopping the growth of bacteria. It is commonly used to treat skin infections, including those caused by S. aureus. The ointment form of Bacitracin is preferred for dry foot lesions as it provides a protective barrier and keeps the affected area moisturized. Surgical debridement may be necessary in severe cases where there is extensive tissue damage or if the infection does not respond to antibiotic treatment.

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21. Staphylococcus

Explanation

Staphylococcus is a genus of bacteria that is known to be Gram positive. This means that when stained with the Gram stain, these bacteria retain the purple color, indicating that they have a thick peptidoglycan layer in their cell wall. Gram positive bacteria are generally more susceptible to certain antibiotics and are often associated with infections such as skin and soft tissue infections, as well as some types of pneumonia.

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22. Most common causative agent of the systemic infection Osteomyelitis

Explanation

S. aureus is the most common causative agent of the systemic infection Osteomyelitis. This bacterium is a common pathogen that can cause various infections in different parts of the body, including bones. It has the ability to invade and infect the bone, leading to inflammation and destruction of bone tissue. Other organisms like S. epidermidis and S. saprophyticus can also cause osteomyelitis, but they are less common compared to S. aureus.

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23. Linezolid (Zyvox) and Synercid are two drugs that treat MRSA. How?

Explanation

Linezolid (Zyvox) and Synercid are both drugs that belong to the class of antibiotics known as protein synthesis inhibitors. These drugs work by inhibiting the synthesis of proteins in bacteria, including MRSA (methicillin-resistant Staphylococcus aureus). By targeting the bacterial protein synthesis machinery, Linezolid and Synercid effectively prevent the bacteria from producing essential proteins needed for their growth and survival. This ultimately leads to the death of the MRSA bacteria and helps in treating the infection caused by these resistant strains.

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24. The following applies to which Streptolysin of Streptococcus pyogenes? An increase in antibody titer is used to determine if individual had recent S. pyogenes infection

Explanation

An increase in antibody titer is used to determine if an individual had a recent Streptococcus pyogenes infection. SLO (Streptolysin O) is a hemolysin produced by Streptococcus pyogenes that is responsible for the lysis of red blood cells. Antibodies against SLO are produced by the immune system in response to an infection with Streptococcus pyogenes. Therefore, an increase in antibody titer against SLO indicates a recent infection with Streptococcus pyogenes.

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25. How are saprophyticus and epidermidis different from aureus in terms of coagulase and DNase?

Explanation

The correct answer is that aureus is positive. This means that Staphylococcus aureus produces coagulase and DNase enzymes, while Staphylococcus saprophyticus and Staphylococcus epidermidis do not produce these enzymes. Coagulase is an enzyme that causes blood to clot, while DNase is an enzyme that breaks down DNA. This difference in enzyme production is one way to distinguish between these three species of Staphylococcus bacteria.

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26. Staphylococcus

Explanation

Staphylococcus is a genus of bacteria that includes several species. The given information states that Staphylococcus is "Catalase (peroxidase) Positive." This means that the bacteria produce the enzyme catalase, which helps in breaking down hydrogen peroxide into water and oxygen. This characteristic is useful in differentiating Staphylococcus from other bacteria that are catalase negative.

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27. All of the following are localized infections produced by S. aureus except

Explanation

Shingles is caused by the varicella-zoster virus, not by S. aureus. It is a viral infection that affects the nerve roots and causes a painful rash. The other options, impetigo, cellulitis, folliculitis, and furuncles and carbuncles, are all localized infections that can be caused by S. aureus.

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28. Pyelonephritis is 

Explanation

Pyelonephritis is an infection that affects the kidneys, specifically the renal pelvis and the kidney tissue. It is considered an upper urinary tract infection (UTI) because it involves the upper part of the urinary system, which includes the kidneys and the ureters. Lower UTIs, on the other hand, involve the lower part of the urinary system, such as the bladder and the urethra. Therefore, the correct answer is Upper UTI.

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29. Streptolysin O (SLO)

Explanation

Streptolysin O (SLO) is considered immunogenic because it is capable of eliciting an immune response in the body. This means that when SLO enters the body, the immune system recognizes it as foreign and mounts a response to eliminate it. This immune response may involve the production of antibodies specific to SLO, as well as the activation of immune cells to destroy the pathogen. Therefore, SLO is immunogenic because it can stimulate an immune response.

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30. Systemic infection caused by S. aureus in which inhalation can lead to pneumonia, pulmonary abvesses or necrosis of host cells in bronchial tree or any lung cavity

Explanation

Post-viral lobar pneumonia is the most appropriate explanation for the given correct answer. Post-viral lobar pneumonia refers to a type of pneumonia that occurs after a viral infection, such as influenza or respiratory syncytial virus (RSV). In this case, the systemic infection caused by S. aureus can lead to pneumonia, pulmonary abscesses, or necrosis of host cells in the bronchial tree or any lung cavity. This aligns with the concept of post-viral lobar pneumonia, which is characterized by inflammation and infection in the lung tissue following a viral infection.

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31. Streptococci have what cell arrangement? 

Explanation

Streptococci have a chain-like cell arrangement. This means that the cells are arranged in a linear fashion, resembling a chain. This arrangement is characteristic of streptococci bacteria and distinguishes them from other bacteria that may have different cell arrangements, such as grape-like clusters.

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32. Which is sub-grouped based on the Lancefield Groupings (A-H, K-M, O-V) based on the C carbohydrate extracted from the cell wall with hot HCl treatment?

Explanation

Streptococcus is sub-grouped based on the Lancefield Groupings (A-H, K-M, O-V) based on the C carbohydrate extracted from the cell wall with hot HCl treatment.

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33. Sugar fermentation and esculin hydrolysis are the biotyping/biochemical properties of 

Explanation

Sugar fermentation and esculin hydrolysis are two specific biochemical properties that are characteristic of Streptococcus bacteria. Streptococcus species are known to ferment sugars, meaning they can break down sugars for energy production. Additionally, they are also capable of hydrolyzing esculin, a compound found in certain plants, into glucose and esculetin. These properties are useful in differentiating Streptococcus from other bacterial genera, such as Staphylococcus and Bacillus, which may not exhibit the same fermentation or hydrolysis capabilities.

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34. S. aureus

Explanation

The given correct answer suggests that S. aureus is Mannitol positive. This means that S. aureus can ferment mannitol, a type of sugar, and produce acid as a byproduct. This characteristic is often used in the laboratory to differentiate S. aureus from other bacteria.

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35. Toxin A and B, which are exotoxins of S. aureus, are what kind of exotoxins?

Explanation

Toxin A and B, exotoxins of S. aureus, are classified as enterotoxins. Enterotoxins are toxins that primarily affect the gastrointestinal system, causing symptoms such as vomiting and diarrhea. These toxins are produced by certain bacteria, including S. aureus, and are typically ingested through contaminated food or water. In the case of S. aureus, enterotoxins are responsible for food poisoning, as they are heat-stable and can withstand cooking temperatures.

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36. S. epidermidis systemic infections have what origin?

Explanation

S. epidermidis systemic infections have their origin in hospitals. Hospitals provide an environment that is conducive to the growth and spread of S. epidermidis bacteria, which can cause systemic infections. Factors such as close proximity of patients, compromised immune systems, invasive medical procedures, and the presence of medical devices make hospitals a common source of S. epidermidis infections.

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37. How are both Staph saprophyticus and Staph epidermidis different from S. aureus in terms of hemolysis pattern?

Explanation

Staph saprophyticus and Staph epidermidis both exhibit gamma hemolysis, while Staph aureus displays beta hemolysis.

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38. Which staph can cause both pyelonephritis and cystitis?

Explanation

Staphylococcus saprophyticus can cause both pyelonephritis and cystitis. This bacterium is commonly associated with urinary tract infections, particularly in young sexually active women. It has the ability to adhere to the urinary tract lining and cause inflammation in both the kidneys (pyelonephritis) and the bladder (cystitis). Staphylococcus aureus, epidermidis, and pyogenes are not typically associated with urinary tract infections.

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39. Is Staph saprophyticus coagulase negative or positive?

Explanation

Staphylococcus saprophyticus is a coagulase-negative bacterium. Coagulase is an enzyme produced by some Staphylococcus species, such as Staphylococcus aureus, which causes the plasma protein fibrinogen to clot. Since Staphylococcus saprophyticus does not produce coagulase, it is classified as coagulase-negative.

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40. Pyruria (Pus in the urine) is commonly due to which Staph?

Explanation

Pyruria, which is the presence of pus in the urine, is commonly caused by Staphylococcus saprophyticus. This bacterium is a common cause of urinary tract infections, particularly in young sexually active women. Staphylococcus aureus is more commonly associated with skin and soft tissue infections, while Staphylococcus epidermidis is a common cause of infections related to medical devices. Staphylococcus pyogenes, also known as Group A Streptococcus, is not a Staphylococcus species and is not typically associated with pyruria.

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41. Halophilic (halotolerant); will grow in presence of 7.5% NaCl

Explanation

Staphylococcus is the correct answer because it is a halophilic (halotolerant) bacterium that can tolerate and grow in the presence of 7.5% NaCl. This means that Staphylococcus can survive and thrive in high salt concentrations, making it well-adapted to environments with high salt content such as the skin and mucous membranes. Streptococcus, on the other hand, is not known for its ability to tolerate high salt concentrations, so it is not the correct answer in this context.

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42. Topical treatment for S. aureus

Explanation

Bacitracin is a topical treatment for S. aureus because it is effective against gram-positive bacteria, including S. aureus. It works by inhibiting the cell wall synthesis of bacteria, leading to their death. Bacitracin is commonly used in ointments and creams to treat skin infections caused by S. aureus. It is not effective against methicillin-resistant S. aureus (MRSA), but it can still be used to treat other strains of S. aureus.

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43. This exists. 

Explanation

The correct answer is ASO (antibodies to SLO). This suggests that the existence referred to in the question is related to the presence of antibodies to SLO. The options ASL (antibodies to SLS) and ASO and ASL are not chosen as the answer, indicating that the existence mentioned is specifically associated with antibodies to SLO.

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44. Streptococcus pyogenes falls into which group

Explanation

Streptococcus pyogenes falls into Group A. This classification is based on the Lancefield grouping system, which categorizes streptococci based on the antigens present on their cell walls. Group A streptococci, including Streptococcus pyogenes, have specific carbohydrates on their cell walls that are recognized by antibodies in the Group A Lancefield antigen test. This test is commonly used to identify and differentiate Group A streptococci from other groups.

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45. M. luteus is what type of species

Explanation

M. luteus is classified as a species of Micrococcus.

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46. Corynebacteria species are also known as

Explanation

Corynebacteria species are commonly referred to as diphtheroids. Diphtheroids are a group of bacteria that resemble the bacterium responsible for causing diphtheria, but they do not produce the toxin associated with the disease. These bacteria are commonly found on the skin, mucous membranes, and in other areas of the body. They are considered part of the normal flora and typically do not cause disease unless there is an underlying condition or weakened immune system.

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47. More drug resistant

Explanation

Nosocomially acquired MRSA refers to Methicillin-resistant Staphylococcus aureus (MRSA) infections that are acquired in healthcare settings such as hospitals or nursing homes. This type of MRSA is typically more drug-resistant compared to community-associated MRSA, which is acquired outside of healthcare settings. The correct answer suggests that nosocomially acquired MRSA is the more drug-resistant form of the infection.

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48. Erythrogenic toxin of Strep pyogenes is a superantigen

Explanation

The erythrogenic toxin produced by Streptococcus pyogenes is classified as a superantigen. Superantigens are substances that can activate a large number of T cells, leading to an excessive immune response. In the case of the erythrogenic toxin, it specifically activates T cells that express certain V beta chains, resulting in the characteristic rash seen in scarlet fever. Therefore, the statement that the erythrogenic toxin of Strep pyogenes is a superantigen is true.

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49. Is Staph saprophyticus DNase positive or negative?

Explanation

Staphylococcus saprophyticus is a species of bacteria that is commonly found in the urinary tract and is a common cause of urinary tract infections (UTIs) in young women. DNase is an enzyme that breaks down DNA. The question is asking whether Staph saprophyticus is DNase positive or negative. The correct answer is "Negative" because Staph saprophyticus is typically DNase negative, meaning it does not produce the DNase enzyme. This is an important characteristic used in identifying and differentiating Staph saprophyticus from other Staphylococcus species.

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50. Which bacteria can be highly invasive?

Explanation

Streptococcus bacteria can be highly invasive because they have the ability to produce enzymes and toxins that allow them to penetrate and damage host tissues. They can also evade the immune system and spread throughout the body, causing severe infections such as pneumonia, meningitis, and sepsis. Staphylococcus bacteria, on the other hand, can also cause invasive infections but are generally less invasive compared to Streptococcus.

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51. Molecular mimicry seen in the hyaluronic capsule of ____________ makes the capsule not immunogenic 

Explanation

Streptococcus pyogenes has a hyaluronic capsule that contains molecules that resemble the host's own tissues. This molecular mimicry helps the bacteria evade the immune system because the immune system recognizes the capsule as self and does not mount an immune response against it. This property makes the hyaluronic capsule of Streptococcus pyogenes not immunogenic.

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52. Which Staph may infect the urinary tract of patients due to poor hygiene and sexual activity?

Explanation

S. saprophyticus may infect the urinary tract of patients due to poor hygiene and sexual activity. This particular strain of Staphylococcus is commonly found in the genital area and can easily be transmitted during sexual intercourse. Additionally, poor hygiene practices can contribute to the growth and spread of S. saprophyticus, increasing the risk of urinary tract infections.

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53. What is the primary habitat of Streptococci?

Explanation

Streptococci are primarily found in the mammalian nasopharynx, which is the upper part of the throat behind the nose. This is their primary habitat where they thrive and reproduce. They are commonly found in this area and can cause various infections such as strep throat. Streptococci are less commonly found in the mammalian GI tract and skin compared to the nasopharynx.

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54. _________ have an oral and enteric clinical presenation and its manifestations include pyogenesis (pus formation)

Explanation

Streptococcus is the correct answer because it is a genus of bacteria that can cause oral and enteric infections. These infections often result in the formation of pus, known as pyogenesis. Staphylococcus is another genus of bacteria that can cause similar infections, but it is not the best answer in this case. Planococcus and Stomatococcus are not typically associated with oral and enteric infections or pus formation.

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55. P-V leukocidin associated with 

Explanation

P-V leukocidin is a toxin that is associated with Community-associated MRSA (methicillin-resistant Staphylococcus aureus). This toxin is produced by certain strains of MRSA and is responsible for damaging white blood cells, specifically the polymorphonuclear leukocytes (PMNs). Community-associated MRSA refers to MRSA infections that are acquired outside of healthcare settings, such as in the community or in sports teams. This type of MRSA is often more virulent and can cause severe skin and soft tissue infections. The presence of P-V leukocidin in Community-associated MRSA strains contributes to their pathogenicity and ability to evade the immune system.

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56. Which exotoxin of S.aureus causes excessive release of IL-2 from T-helper cells and IL-1 from macrophages leading to hypotension, multiple organ involvement and death, produced only by lysogenized isolates during their growth?

Explanation

TSST (Toxic Shock Syndrome Toxin) is an exotoxin produced by certain strains of Staphylococcus aureus bacteria. It causes excessive release of IL-2 from T-helper cells and IL-1 from macrophages, leading to hypotension, multiple organ involvement, and potentially death. TSST is only produced by lysogenized isolates of S. aureus during their growth. This toxin is associated with toxic shock syndrome, a severe and potentially life-threatening condition.

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57. Frank pathogen, as opposed to opportunistic commensal

Explanation

S. aureus is the correct answer because it is a pathogen, meaning it is capable of causing disease in a host. In contrast, S. epidermidis and S. saprophyticus are considered opportunistic commensals, which means they typically live harmlessly on or in a host but can cause infection or disease under certain circumstances. Therefore, S. aureus is more likely to cause illness or infection compared to the other two options.

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58. Color of Staph epidermidis

Explanation

Staph epidermidis is a type of bacteria that commonly resides on human skin. It is typically white in color when grown in laboratory cultures. This color is due to the absence of pigments or the presence of light-colored pigments. The white color of Staph epidermidis helps to distinguish it from other bacteria that may have different colors when grown in cultures.

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59. Streptokinase of Strep pyogenes 

Explanation

Streptokinase is an enzyme produced by Streptococcus pyogenes that plays a role in breaking down blood clots. It works by activating plasmin, an enzyme responsible for dissolving fibrin, the protein that forms the structure of blood clots. By activating plasmin, streptokinase helps to break down clots and restore blood flow. Therefore, the correct answer is that streptokinase activates plasmin to lyse clots.

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60. You can get antibody formation with which Streptolysin of Streptococcus pyogenes?

Explanation

SLO, also known as Streptolysin O, is a protein produced by Streptococcus pyogenes. It is a potent toxin that can cause cell lysis and tissue damage. When S. pyogenes infects the body, the immune system responds by producing antibodies, including antibodies against SLO. These antibodies help to neutralize the toxin and prevent further damage. Therefore, SLO can induce antibody formation in response to S. pyogenes infection.

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61. Where is Toxin A preformed?

Explanation

Toxin A is preformed in food. This means that the toxin is already present in the food before it is consumed. It is important to be cautious about the quality and safety of the food we consume to avoid any potential toxins or contaminants that may be present.

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62. Strep mutans is what kind of strep?

Explanation

The correct answer is viridans Strep. Strep mutans is a type of bacteria that belongs to the viridans Streptococci group. This group includes various species of streptococci that are commonly found in the oral cavity. Strep mutans is known for its role in dental caries and is one of the primary bacteria involved in tooth decay.

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63. Systemic infection caused by S. aureus that shows as an increased temperature due to release of pyrogens from bacteria, may lead to sinusitis, meningitis, and parotitis

Explanation

Bacteremia and sepsis refer to a systemic infection caused by the bacteria S. aureus. This infection can lead to various complications such as sinusitis, meningitis, and parotitis. The release of pyrogens from the bacteria can cause an increased temperature, which is a common symptom of systemic infection. Therefore, the given answer is correct as it accurately describes the consequences of a systemic infection caused by S. aureus.

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64. Staph epidermidis

Explanation

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65. Which of the following are sensitive to Novobiocin?

Explanation

Novobiocin is an antibiotic that inhibits the activity of DNA gyrase, an enzyme involved in DNA replication. S. aureus and S. epidermidis are both sensitive to Novobiocin because they rely on DNA gyrase for their DNA replication process. S. saprophyticus, on the other hand, is not sensitive to Novobiocin as it has a different mechanism for DNA replication that does not involve DNA gyrase. Therefore, the correct answer is S. aureus, S. epidermidis.

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66. S. aureus causes

Explanation

S. aureus causes food intoxication via enterotoxin A. This means that when S. aureus bacteria contaminate food, they produce enterotoxin A which is then ingested by individuals consuming the contaminated food. Enterotoxin A is a heat-stable toxin that can withstand high temperatures, so even if the food is cooked, the toxin remains active and can cause illness. Symptoms of food intoxication caused by enterotoxin A include nausea, vomiting, abdominal cramps, and diarrhea. This type of foodborne illness is typically rapid in onset, occurring within a few hours of consuming the contaminated food.

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67. Nuclease of Strep pyogenes does this

Explanation

The nuclease of Strep pyogenes is capable of degrading both DNA and RNA. Nucleases are enzymes that break down nucleic acids, which are the building blocks of DNA and RNA. In this case, the nuclease from Strep pyogenes has the ability to degrade both types of nucleic acids, making it a versatile enzyme for the breakdown of genetic material.

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68. S. mucilaginous is an example of what type of microorganism?

Explanation

Stomatococcus is the correct answer because S. mucilaginous is a species of Stomatococcus. Stomatococcus is a type of microorganism that belongs to the family Micrococcaceae. It is a Gram-positive, non-motile, and non-spore-forming bacterium. Stomatococcus species are commonly found in the environment, including soil, water, and plants. They are also known to be associated with infections in humans and animals. Therefore, S. mucilaginous can be classified as a type of microorganism within the Stomatococcus genus.

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69. Toxin A of S. aureus causes

Explanation

Toxin A of S. aureus causes food intoxication. This is a condition that occurs when a person consumes food contaminated with the toxin produced by Staphylococcus aureus bacteria. Symptoms of food intoxication include nausea, vomiting, diarrhea, and abdominal cramps. The toxin produced by S. aureus can withstand high temperatures, so even reheating the contaminated food may not eliminate the toxin.

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70. Which exotoxin of S. aureus is a superantigen?

Explanation

TSST, or toxic shock syndrome toxin, is a superantigen produced by S. aureus. Superantigens are capable of activating a large number of T cells, leading to an excessive immune response. TSST specifically binds to major histocompatibility complex class II molecules on antigen-presenting cells, which results in the activation of a large number of T cells and the release of pro-inflammatory cytokines. This excessive immune response can lead to the symptoms of toxic shock syndrome, such as fever, rash, and organ failure. Exfoliatin, alpha toxin, and beta toxin are other exotoxins produced by S. aureus, but they do not function as superantigens.

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71. Streptococci have what hemolytic properties

Explanation

Streptococci have alpha, beta, and gamma hemolytic properties. This means that they can cause different degrees of red blood cell destruction. Alpha-hemolytic streptococci partially break down red blood cells, resulting in a greenish discoloration around the colony. Beta-hemolytic streptococci completely break down red blood cells, creating a clear zone around the colony. Gamma-hemolytic streptococci do not have any hemolytic properties and do not cause any change in the blood agar. Therefore, streptococci can exhibit all three types of hemolysis.

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72. Which types of S. aureus produce exfoliatin?

Explanation

Exfoliatin is a toxin produced by certain strains of Staphylococcus aureus. It causes a blistering skin condition known as staphylococcal scalded skin syndrome (SSSS). The production of exfoliatin is associated with lysogenized isolates of S. aureus, specifically those belonging to phage group 2. Lysogeny refers to the integration of a bacteriophage into the bacterial genome, which can result in the transfer of genetic material, including virulence factors like exfoliatin. Therefore, the correct answer is phage group 2 (Lysogenized isolates).

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73. This S. epidermidis virulence factor has adhesion to host tissue and plastics, anti-phagocytic, blocks antibiotic penetration

Explanation

The correct answer is exopolysaccharide glycocalyx (slime layer). The slime layer produced by S. epidermidis acts as a virulence factor by allowing the bacteria to adhere to host tissues and plastics, which facilitates colonization and infection. It also has anti-phagocytic properties, preventing phagocytosis by immune cells. Additionally, the slime layer acts as a barrier, blocking the penetration of antibiotics, making the bacteria more resistant to treatment.

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74. In Strep pyogenes, there are at least how many different serotypes of M protein

Explanation

Strep pyogenes, also known as Group A Streptococcus, is a bacterium that causes various infections in humans. The M protein is a virulence factor produced by this bacterium, which helps it evade the host's immune system. The M protein is highly variable, and different strains of Strep pyogenes can have different types of M protein. It is estimated that there are at least 100 different serotypes of M protein in Strep pyogenes. These serotypes contribute to the bacterium's ability to cause different diseases and evade immune responses, making it a challenging pathogen to combat.

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75. Ingestion of pre-formed toxin

Explanation

Food intoxication refers to the ingestion of food that contains toxins produced by bacteria or other microorganisms. In the case of botulism, it is caused by the ingestion of food contaminated with the Clostridium botulinum bacteria, which produces a potent neurotoxin. This toxin can cause severe illness and paralysis. Therefore, the ingestion of pre-formed toxin is the correct explanation for botulism, making food intoxication the appropriate answer.

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76. Staphylokinase opposes what virulance factor of S. aureus?

Explanation

Staphylokinase opposes the virulence factor of S. aureus known as coagulase. Coagulase is an enzyme produced by S. aureus that causes blood to clot, which helps the bacteria evade the immune system and form protective barriers. Staphylokinase, on the other hand, is a protein produced by S. aureus that can dissolve blood clots. By opposing coagulase, staphylokinase allows the bacteria to spread and invade other tissues more easily.

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77. This should be suspected with any topical S. aureus infection of the foot

Explanation

This answer is correct because osteomyelitis is a serious infection of the bone that can occur in any part of the body, including the foot. Staphylococcus aureus is a common cause of osteomyelitis, so it should be suspected in any topical S. aureus infection of the foot. Osteomyelitis can cause symptoms such as pain, swelling, and redness in the affected area, and if left untreated, it can lead to complications such as bone destruction and chronic infection.

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78. Clumping factor associated with endocarditis as it adheres to heart valves

Explanation

Coagulase is the correct answer because it is an enzyme produced by Staphylococcus aureus that causes the formation of blood clots. This clumping factor is significant in the context of endocarditis as it allows the bacteria to adhere to heart valves, leading to the formation of vegetations. The ability of Staphylococcus aureus to produce coagulase contributes to its virulence and the development of complications associated with endocarditis.

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79. It is not possible to carry S. aureus and be unaffected

Explanation

The statement is false because it is possible to carry S. aureus (a type of bacteria) without showing any symptoms or being affected by it. Many people can be carriers of S. aureus in their nose, throat, or skin without experiencing any illness. However, they can still transmit the bacteria to others who may become infected and show symptoms. Therefore, carrying S. aureus does not necessarily mean being affected by it.

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80. In Strep pyogenes, certain M proteins resemble sarcolemmal membrane protein of the hearth thereby leading to 

Explanation

Certain M proteins in Strep pyogenes resemble sarcolemmal membrane proteins of the heart, which can lead to an immune response that mistakenly attacks the heart tissue. This immune response can cause inflammation and damage to the heart valves, leading to rheumatic fever. Scarlet fever is caused by a different mechanism involving toxins produced by the bacteria, while necrotizing fasciitis is a severe skin and soft tissue infection caused by the bacteria.

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81. Strep pyogenes does not have hyaluronidase activity

Explanation

Strep pyogenes does have hyaluronidase activity. Hyaluronidase is an enzyme that breaks down hyaluronic acid, which is a component of connective tissue. Strep pyogenes produces hyaluronidase as one of its virulence factors, allowing it to spread through tissues more easily. Therefore, the correct answer is False.

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82. Streptococci

Explanation

Streptococci are a group of bacteria that can be categorized based on their ability to produce the enzyme catalase. Catalase-positive streptococci have the ability to break down hydrogen peroxide into water and oxygen, while catalase-negative streptococci lack this ability. Therefore, the correct answer is "Catalase Negative" because it indicates that the streptococci being referred to in the question do not produce the catalase enzyme.

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83. What does beta lactamase lead to?

Explanation

Beta lactamase is an enzyme that is produced by certain bacteria, and its main function is to break down beta-lactam antibiotics, such as penicillin. When beta lactamase is present, it can inactivate penicillin, rendering it ineffective against the bacteria. Therefore, beta lactamase leads to penicillin resistance, as the bacteria are able to survive and multiply in the presence of penicillin.

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84. Which Staphylococcus has Exopolysaccharide Glycocalyx aka SLIME LAYER as a virulence factor?

Explanation

S. epidermidis has Exopolysaccharide Glycocalyx aka SLIME LAYER as a virulence factor. This means that S. epidermidis is capable of producing a slimy layer of exopolysaccharides that helps it adhere to surfaces, including medical devices like catheters. This slime layer provides protection against the immune system and antibiotics, allowing the bacteria to establish infections. S. aureus and S. saprophyticus do not have this specific virulence factor.

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85. Is Staph saphrophyticus Mannitol positive or negative?

Explanation

The answer "It varies" is correct because Staphylococcus saprophyticus can exhibit both Mannitol positive and Mannitol negative reactions. Mannitol fermentation is a characteristic used to differentiate between different species of Staphylococcus bacteria. Some strains of Staphylococcus saprophyticus can ferment Mannitol, resulting in a positive reaction, while others cannot, leading to a negative reaction. Therefore, the Mannitol reaction of Staphylococcus saprophyticus can vary depending on the specific strain.

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86. Lancefield grouping scheme was developed for what purpose?

Explanation

The Lancefield grouping scheme was developed to differentiate between beta hemolytic streptococci. This scheme categorizes these bacteria based on the presence of specific antigens on their cell walls. By identifying these antigens, healthcare professionals can determine the type of streptococcal infection and prescribe appropriate treatment. This grouping system is particularly useful in clinical settings for accurate diagnosis and management of infections caused by beta hemolytic streptococci.

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87. Streptococcus pyogenes colonizes which 2 areas?

Explanation

Streptococcus pyogenes colonizes the skin and oropharynx. This bacterium is commonly found on the skin, where it can cause infections such as impetigo. It also colonizes the oropharynx, which includes the back of the throat and tonsils. In the oropharynx, it can cause various infections such as strep throat and tonsillitis. Therefore, the correct answer is skin and oropharynx.

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88. Is Strep pyogenes hyaluronic acid capsule immunogenic?

Explanation

The answer is "No - not recognized as foreign" because Strep pyogenes is a human pathogen and its hyaluronic acid capsule is similar to the hyaluronic acid found in human tissues. Therefore, the immune system does not recognize it as foreign and does not mount an immune response against it.

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89. Streptolysin O (SLO)  _______ in presence of oxygen

Explanation

Streptolysin O (SLO) is oxygen sensitive or labile, meaning it is easily deactivated or destroyed in the presence of oxygen. This implies that SLO's activity or effectiveness is reduced or completely lost when exposed to oxygen.

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90. SLS

Explanation

The correct answer is "Stable in the presence of oxygen". This means that SLS (Sodium Lauryl Sulfate) is not easily affected or decomposed by oxygen. It can maintain its stability and properties even when exposed to oxygen. This is an important characteristic as it allows SLS to be used in various products, such as detergents and personal care items, where oxygen is present.

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91. UTIs are systemic infections of which Staph?

Explanation

not-available-via-ai

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92. Systemic infection associated with S. aureus that affects the bone epiphysis in adults, common in the tropics, often accompanied with pyomyositis

Explanation

Osteomyelitis is a systemic infection caused by S. aureus that affects the bone epiphysis in adults. It is more common in tropical regions and is often accompanied by pyomyositis. This infection can cause inflammation, pain, and destruction of the affected bone. It can be a serious condition that requires prompt medical treatment, including antibiotics and possible surgical intervention.

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93. Which bacteria are the most important bacteria, medically speaking?

Explanation

Streptococcus is considered one of the most important bacteria medically because it is responsible for causing a wide range of infections in humans. It can cause strep throat, pneumonia, skin infections, and even life-threatening conditions such as sepsis and meningitis. Streptococcus bacteria are also known for their ability to develop antibiotic resistance, making them a significant concern in healthcare settings. Therefore, understanding and effectively treating Streptococcus infections is crucial for medical professionals in order to prevent and manage these potentially serious infections.

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94. The immunogenicity of SLO is important for which 2 medical conditions

Explanation

The immunogenicity of SLO (streptolysin O) is important for Rheumatic fever and Acute glomerulonephritis. Rheumatic fever is an inflammatory disease that can occur after a streptococcal infection, and SLO is one of the antigens produced by the bacteria that can trigger an immune response leading to the development of the disease. Acute glomerulonephritis is also associated with streptococcal infections, and the immune response to SLO can contribute to the inflammation and damage of the glomeruli in the kidneys, leading to the development of the condition.

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95. This virulence factor of Strep. pyogenes causes the red rash of Scarlet fever

Explanation

Erythrogenic toxin is a virulence factor produced by Streptococcus pyogenes that causes the characteristic red rash seen in Scarlet fever. This toxin is responsible for the bright red color of the rash and is released by the bacteria during infection. It acts by damaging the blood vessels, leading to leakage of blood into the surrounding tissues and the development of the rash. The presence of erythrogenic toxin is a key factor in the pathogenesis of Scarlet fever and helps differentiate it from other streptococcal infections.

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96. This tests for the susceptibility to erythrogenic toxin of Strep pyogenes

Explanation

The Dick test is used to test for the susceptibility to erythrogenic toxin produced by Streptococcus pyogenes. This toxin is responsible for causing the characteristic rash seen in diseases such as scarlet fever. The test involves injecting a small amount of the toxin into the skin and observing for a localized reaction. A positive reaction indicates that the individual is susceptible to the toxin and may be at risk for developing erysipelas or other infections caused by Strep pyogenes.

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97. Nuclease of strep pyogenes is a spreading factor because it

Explanation

The nuclease of strep pyogenes is a spreading factor because it decreases pus viscosity. Pus is a thick, yellowish fluid that is formed at the site of infection. It consists of dead white blood cells, bacteria, and tissue debris. By decreasing the viscosity of pus, the nuclease helps in spreading the infection to surrounding tissues. This allows the bacteria to invade and colonize new areas, leading to the spread of the infection.

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98. Staph saprophyticus is resistant to which antibiotic?

Explanation

Staphylococcus saprophyticus is known to be resistant to Novobiocin. This antibiotic is not effective against this particular strain of Staphylococcus bacteria.

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99. What do mutant penicillin-binding proteins result in?

Explanation

Mutant penicillin-binding proteins result in methicillin resistance. Methicillin is a type of antibiotic that targets penicillin-binding proteins in bacteria, inhibiting cell wall synthesis and leading to bacterial death. However, mutant penicillin-binding proteins can undergo changes that make them less susceptible to the inhibitory effects of methicillin, resulting in methicillin resistance. This means that the bacteria are able to survive and continue growing even in the presence of methicillin, making it difficult to treat infections caused by these resistant strains.

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100. Which 2 medically important Streptococci cannot be classified by "C" antigen?

Explanation

Streptococcus pneumoniae and viridans streptococci are two medically important types of Streptococci that cannot be classified by "C" antigen. The "C" antigen is used to classify Streptococci into different groups based on the presence or absence of this antigen. However, both pneumoniae and viridans streptococci do not possess this antigen, making them unable to be classified using this method.

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101. Streptococcus pyogenes has which hemolysis pattern?

Explanation

Streptococcus pyogenes exhibits the beta hemolysis pattern. This means that it completely lyses red blood cells and produces a clear zone around the bacterial colonies on blood agar. This pattern is characterized by the destruction of red blood cells and the release of hemoglobin, resulting in a clear zone around the colonies.

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102. Streptococcus pyogenes

Explanation

The given answer, "Catalase Negative," suggests that Streptococcus pyogenes does not produce the enzyme catalase. Catalase is an enzyme that helps in the breakdown of hydrogen peroxide into water and oxygen. Bacteria that are catalase positive can break down hydrogen peroxide, resulting in the production of bubbles of oxygen gas. In contrast, catalase-negative bacteria do not produce bubbles when hydrogen peroxide is added. Therefore, based on the given information, Streptococcus pyogenes is likely unable to break down hydrogen peroxide and is catalase negative.

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103. Strep anginosus is what kind of strep?

Explanation

The correct answer is Mixed type. This is because Strep anginosus is a group of bacteria that includes different species, such as Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius. These species are often found together in infections, leading to the classification of Strep anginosus as a mixed type of strep.

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104. Which exotoxin of S. aureus is most common?

Explanation

Toxin A is the most common exotoxin produced by S. aureus. This toxin is responsible for a variety of symptoms and diseases caused by the bacteria, including food poisoning, skin infections, and toxic shock syndrome. It is produced by most strains of S. aureus and is one of the main virulence factors of the bacteria.

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105. Catalyzes the formation of thrombin which converts fibrinogen to fibrin

Explanation

Coagulase is an enzyme that plays a crucial role in the clotting process of blood. It catalyzes the conversion of prothrombin to thrombin, which in turn converts fibrinogen into fibrin. Fibrin is a fibrous protein that forms a mesh-like structure, leading to the formation of blood clots. Therefore, coagulase promotes the clotting of blood by facilitating the formation of thrombin and subsequent conversion of fibrinogen to fibrin.

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106. In scalded skin syndrome (Ritter's disease), isolates lysogenized by Phage Group II produce

Explanation

In scalded skin syndrome (Ritter's disease), isolates lysogenized by Phage Group II produce exfoliatin. Exfoliatin is a toxin that causes the skin to peel off, resulting in the characteristic symptoms of scalded skin syndrome. This toxin is produced by certain strains of Staphylococcus aureus bacteria that have been infected by a specific bacteriophage (virus). The exfoliatin toxin causes the detachment of the upper layers of the skin, leading to the formation of large blisters and the shedding of skin.

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107. Attachment to epithelial cells via hemagglutinins and other cell surface proteins is a virulence factor of which staph?

Explanation

The attachment to epithelial cells via hemagglutinins and other cell surface proteins is a virulence factor of S. saprophyticus. This means that S. saprophyticus has the ability to adhere to and invade epithelial cells, which contributes to its ability to cause infection and disease. This virulence factor is not present in S. aureus, S. epidermidis, or S. pyogenes.

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108. This affects only abnormal or damaged heart valves, and prosthetic valves

Explanation

Subacute bacterial endocarditis is the correct answer because it is a condition that affects abnormal or damaged heart valves, as well as prosthetic valves. Unlike acute bacterial endocarditis, which develops rapidly and is typically caused by aggressive bacteria, subacute bacterial endocarditis progresses more slowly and is commonly caused by less aggressive bacteria. Therefore, this condition aligns with the given information that it affects only abnormal or damaged heart valves and prosthetic valves.

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109. Causes tissue necrosis and acts like a detergent

Explanation

Gamma toxin causes tissue necrosis and acts like a detergent. This means that it has the ability to damage and kill cells, leading to tissue death. Additionally, it acts like a detergent, which suggests that it has the ability to disrupt cell membranes and break down cellular structures. This combination of tissue necrosis and detergent-like activity makes gamma toxin a potent and destructive toxin.

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110. Which drug is not appropriate for treating MRSA/VISA/GISA

Explanation

Clindomycin is not an appropriate drug for treating MRSA/VISA/GISA. This is because it has limited activity against these bacteria and is not effective in eradicating them. Linezolid (Zyvox), Synercid, and Daptomycin, on the other hand, are all effective options for treating MRSA/VISA/GISA infections.

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111. Staph saprophyticus does which type of hemolysis?

Explanation

Staphylococcus saprophyticus is a species of bacteria that is commonly found in the urinary tract and is a frequent cause of urinary tract infections in young, sexually active women. When it comes to hemolysis, Staphylococcus saprophyticus typically exhibits gamma hemolysis. Gamma hemolysis refers to the absence of hemolysis, meaning that there is no visible change in the blood agar surrounding the bacterial colonies. This indicates that the bacteria do not produce any hemolysins, which are enzymes that can lyse red blood cells.

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112. For moist foot lesions caused by S. aureus, use

Explanation

Bacitracin Cream is the recommended treatment for moist foot lesions caused by S. aureus. Bacitracin is an antibiotic that works by killing the bacteria causing the infection. Cream formulations are usually preferred for moist areas as they provide a moist environment for healing and help prevent the wound from drying out. Bacitracin Ointment can also be used, but ointments are generally greasier and may not be as comfortable for patients. Surgical debridement, on the other hand, is a procedure used to remove dead tissue from a wound and is not the first-line treatment for moist foot lesions caused by S. aureus.

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113. In the dick test, after injection, if a red rash appears, the person

Explanation

The dick test is a skin test used to determine if a person has developed antibodies against a specific antigen. If a red rash appears after the injection, it indicates that the person does not have the antibody against the antigen.

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114. S. aureus has sphingomyelinase activity thanks to this

Explanation

S. aureus has sphingomyelinase activity thanks to the Beta toxin.

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115. This S. aureus virulence factor procures nutrients and decreases pus viscosity

Explanation

Nuclease (DNase aka staphylodornase) is the correct answer because it is a virulence factor produced by S. aureus that helps the bacteria acquire nutrients by breaking down DNA present in pus. Additionally, it decreases the viscosity of pus, making it easier for the bacteria to spread and cause infection. Lipase is an enzyme that hydrolyzes lipids, but it does not directly procure nutrients or decrease pus viscosity. Hyaluronidase is an enzyme that breaks down hyaluronic acid, a component of connective tissue, but it also does not directly procure nutrients or decrease pus viscosity. Staphylokinase is an enzyme that activates plasminogen to form plasmin, which helps the bacteria dissolve fibrin clots, but it does not directly procure nutrients or decrease pus viscosity.

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116. Staphylococcal Colitis (Necrotizing enterocolitis is a superinfection producing which enterotoxin?

Explanation

Staphylococcal Colitis is a condition caused by a superinfection of Staphylococcus bacteria in the intestines. The enterotoxin produced by this bacteria is Enterotoxin B. This toxin is responsible for causing inflammation and damage to the intestinal lining, leading to the symptoms of colitis. Enterotoxin A, C, D, and F are not specifically associated with Staphylococcal Colitis.

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117. Strep pyogenes uses _______ aka streptodornase as a virulence factor

Explanation

Strep pyogenes uses DNase B as a virulence factor. DNase B is an enzyme that breaks down DNA, allowing the bacteria to evade the host immune response and spread throughout the body. This virulence factor helps Strep pyogenes to cause infections and establish itself in the host.

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118. Streptococcus pyogenes is sensitive to which antibiotic?

Explanation

Streptococcus pyogenes is sensitive to Bacitracin. Bacitracin is an antibiotic that is effective against a wide range of bacteria, including Streptococcus pyogenes. It works by inhibiting the synthesis of the bacterial cell wall, leading to the death of the bacteria. Other antibiotics like Novobiocin, Vancomycin, and Penicillin G may be effective against other bacteria, but they are not specifically known for their effectiveness against Streptococcus pyogenes.

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119. Staph epidermidis

Explanation

Gamma hemolysis refers to the absence of hemolysis, which means that there is no breakdown of red blood cells. In the case of Staphylococcus epidermidis, it is commonly associated with gamma hemolysis. This bacterium is a part of the normal flora of the skin and mucous membranes and is considered to be non-pathogenic. It does not produce any toxins that cause the destruction of red blood cells, hence the absence of hemolysis.

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120. Which antiobiotic is used to treat Staph epidermidis?

Explanation

Vancomycin is the correct answer because it is a potent antibiotic that is effective against Staph epidermidis. Staph epidermidis is a type of bacteria that commonly causes infections, particularly in hospital settings. Vancomycin is often used to treat infections caused by Staph epidermidis because it is active against methicillin-resistant Staphylococcus aureus (MRSA), which is a common type of Staph epidermidis. It works by inhibiting the synthesis of the bacterial cell wall, leading to the death of the bacteria. Other antibiotics like penicillin, methicillin, bactrim, and erythromycin may not be as effective against Staph epidermidis or may have a higher risk of resistance.

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121. Is S. saprophyticus urease positive or negative?

Explanation

S. saprophyticus is urease positive, meaning that it has the ability to produce the enzyme urease. Urease is an important enzyme that breaks down urea into ammonia and carbon dioxide. This ability allows S. saprophyticus to survive and grow in environments with high urea concentrations, such as the urinary tract. The production of urease by S. saprophyticus is a key characteristic used in its identification and differentiation from other bacteria.

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122. Is S. aureus part of normal flora?

Explanation

S. aureus is not part of normal flora. Normal flora refers to the microorganisms that naturally reside in or on the human body without causing harm. S. aureus is a pathogenic bacterium that can cause various infections, such as skin infections, pneumonia, and bloodstream infections. It is not typically found as a part of the normal microbial population in healthy individuals.

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123. Staph epidermidis (pick two)

Explanation

Staphylococcus epidermidis is a bacterium that is commonly found on the skin and mucous membranes of humans. It is considered to be coagulase negative, meaning it does not produce the enzyme coagulase, which is used to clot blood. Additionally, Staphylococcus epidermidis is also DNase negative, indicating that it does not produce the enzyme DNase, which is responsible for breaking down DNA. These characteristics help differentiate Staphylococcus epidermidis from other Staphylococcus species and are important in its identification and classification.

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124. This Staph has multiple drug resistances including methicillin, oxacillin, and cephalosporins as a virulence factor

Explanation

S. epidermidis is the correct answer because it is known to have multiple drug resistances, including methicillin, oxacillin, and cephalosporins. This makes it a virulence factor, as it is capable of causing infections that are difficult to treat with common antibiotics. S. aureus and S. saprophyticus may also have drug resistances, but the question specifically mentions S. epidermidis as having these characteristics.

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125. S. aureus and S. epidermidis have two which systemic infections in common?

Explanation

S. aureus and S. epidermidis are both bacteria that commonly cause infections in the bloodstream, known as bacteremia. Bacteremia occurs when bacteria enter the bloodstream, either through a wound or infection in another part of the body. These bacteria can then spread to other organs and tissues, leading to a serious condition called sepsis. Sepsis is a systemic inflammatory response to infection that can cause organ dysfunction and even death. Therefore, both S. aureus and S. epidermidis can cause bacteremia and sepsis as systemic infections.

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126. Which system infection caused by S. aureus is often follows orthopedic surgery?

Explanation

Infective (septic) arthritis is the correct answer because it is a system infection caused by S. aureus that often follows orthopedic surgery. Osteomyelitis is also a system infection caused by S. aureus, but it is not specific to orthopedic surgery. Acute bacterial endocarditis is a different type of infection that affects the heart, not the bones or joints.

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127. Describe M protein of Strep pyogenes (choose two)

Explanation

The M protein of Strep pyogenes is known to have two roles. Firstly, it acts as an anti-phagocytic factor, meaning it helps the bacteria evade phagocytosis by immune cells. This allows the bacteria to survive and multiply in the host. Secondly, the M protein serves as an adhesion factor, specifically binding to lipoteichoic acid on the surface of host cells. This adhesion facilitates the attachment of the bacteria to host tissues, aiding in colonization and infection. Therefore, the M protein of Strep pyogenes plays a dual role in immune evasion and host cell adhesion.

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128. Which 2 virulence factors causes Streptococcus pyogenes to have a pattern of beta-hemolysis

Explanation

SLO and SLS are the two virulence factors that cause Streptococcus pyogenes to have a pattern of beta-hemolysis. SLO (Streptolysin O) is a toxin that forms pores in host cell membranes, leading to cell lysis. SLS (Streptolysin S) is another toxin that disrupts cell membranes. Both of these toxins contribute to the destruction of red blood cells, resulting in the characteristic beta-hemolysis pattern seen in S. pyogenes infections.

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129. This binds to the Fc portion of IgG to block complement binding and opsonization (is a virulence factor of S. aureus)

Explanation

Protein A is the correct answer because it binds to the Fc portion of IgG to block complement binding and opsonization. This ability to interfere with the immune response is a virulence factor of S. aureus.

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130. Strep pyogenes - in strains associated with tissue necrosis (Streptococcal Toxic Shock-like syndrome / necrotizing fasciitis), which virulence factor is found

Explanation

In strains of Strep pyogenes associated with tissue necrosis, the virulence factor that is found is a protease. Proteases are enzymes that break down proteins, and in the case of Strep pyogenes, they can contribute to tissue damage by degrading host tissues and interfering with the immune response. This can lead to the development of conditions such as necrotizing fasciitis, where the infection spreads rapidly and causes tissue death. Streptokinase, nuclease, and adhesion factors are also virulence factors associated with Strep pyogenes, but in this particular scenario, the presence of a protease is the correct answer.

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131. Causes Staph. pseudomembranous enterocolitis (superinfection)

Explanation

Toxin B is the correct answer because it is one of the toxins produced by Staphylococcus aureus that causes pseudomembranous enterocolitis. This condition is a superinfection caused by the overgrowth of Staphylococcus aureus in the gastrointestinal tract. Toxin B is known to be a major virulence factor of Staphylococcus aureus and is responsible for the pathogenesis of pseudomembranous enterocolitis. It causes damage to the intestinal lining, leading to the formation of pseudomembranes and inflammation in the colon.

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132. Staph epidermidis is resistant which antibiotics? (Choose as many as necessary)

Explanation

Staphylococcus epidermidis is resistant to Penicillin, Methicillin, Oxacillin, and Cephalosporins. These antibiotics belong to the beta-lactam class, which targets the cell wall synthesis of bacteria. However, Staphylococcus epidermidis has developed resistance mechanisms, such as producing beta-lactamase enzymes that can inactivate these antibiotics. Therefore, these antibiotics are not effective against Staphylococcus epidermidis infections, and alternative treatment options need to be considered.

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133. In Strep pyogenes, this virulence factor is associated with increased antibody titer which indicates recent S. pyogenes infection, like ASO antibody is useful with respect to rheumatic fever

Explanation

DNase B, also known as streptodornase, is a virulence factor associated with Strep pyogenes. This enzyme is capable of degrading DNA, which helps the bacteria to evade the host immune response. When S. pyogenes infects the body, it triggers the production of antibodies, including anti-DNase B antibodies. Therefore, an increased antibody titer against DNase B indicates recent S. pyogenes infection. This information is valuable in diagnosing and monitoring diseases caused by S. pyogenes, such as rheumatic fever.

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134. Which is not an important spreading factor for S. aureus?

Explanation

Coagulase is not an important spreading factor for S. aureus. Coagulase is an enzyme produced by S. aureus that causes blood plasma to clot. While coagulase plays a role in the evasion of the host immune response, it is not directly involved in the spreading of the bacteria. Other factors such as DNase, staphylokinase, hyaluronidase, and lipase are known to contribute to the ability of S. aureus to invade and spread within the host tissues.

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135. This is motile

Explanation

Planococcus is the correct answer because it is a genus of bacteria that is motile. Motility refers to the ability of an organism to move independently using appendages such as flagella. Micrococcus, Stomatococcus, and Staphylococcus are all genera of bacteria that are non-motile. Therefore, the correct answer is Planococcus.

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136. S. aureus has P-V leukocidin that works with this detergent

Explanation

S. aureus has P-V leukocidin, which is a toxin that works in conjunction with the detergent mentioned in the question. Among the options provided, the only toxin that matches this description is the Gamma toxin.

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137. Virulence factor of S. aureus that activates plasmin leading to the breakdown of fibrin clot, thereby releasing organism in host

Explanation

Staphylokinase is the correct answer because it is a virulence factor of S. aureus that activates plasmin, which leads to the breakdown of fibrin clot. This allows the organism to be released in the host.

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138. Leukotoxin is also known as 

Explanation

not-available-via-ai

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139. Enterotoxins from S. aureus have these three characteristics

Explanation

not-available-via-ai

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140. Which virulence factor of Strep pyogenes is essential for pathogenicity?

Explanation

The M protein is a virulence factor of Strep pyogenes that is essential for pathogenicity. It helps the bacteria evade the immune system by inhibiting phagocytosis and promoting adhesion to host cells. This allows the bacteria to establish infection and cause disease.

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141. Which is not associated with pitted keratolysis

Explanation

Planococcus saprophytis is not associated with pitted keratolysis. Pitted keratolysis is a bacterial infection of the skin characterized by small pits or depressions on the soles of the feet. It is commonly caused by bacteria such as Kytococcus sedentarius, Dermatophilus congolensis, and Corynebacterium species. However, Planococcus saprophytis is not known to be associated with this condition.

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142. If the S. aureus isolate is sensitive, what treatment would you use to get rid of S. aureus?

Explanation

Methicillin would be the treatment of choice to get rid of S. aureus if the isolate is sensitive. Methicillin is a type of penicillinase-resistant penicillin, which means it is effective against penicillin-resistant strains of S. aureus. Methicillin works by inhibiting the synthesis of the bacterial cell wall, leading to the death of the bacteria. Therefore, if the S. aureus isolate is sensitive to methicillin, it would be the appropriate treatment option.

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143. S. aureus and S. epidermidis have which 2 virulence factors in common?

Explanation

S. aureus and S. epidermidis have beta-lactamase and mutant penicillin-binding protein in common. Beta-lactamase is an enzyme that inactivates beta-lactam antibiotics, such as penicillins and cephalosporins. Mutant penicillin-binding protein is a protein involved in cell wall synthesis that has undergone genetic changes, making it less susceptible to the action of beta-lactam antibiotics. These shared virulence factors contribute to the ability of both bacteria to resist the effects of certain antibiotics, making them more difficult to treat.

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144. In Strep pyogenes, which M protein types are associated with invasiveness?

Explanation

The M protein is a virulence factor in Strep pyogenes that helps the bacteria evade the host immune system. Certain M protein types are associated with invasiveness, allowing the bacteria to penetrate and infect deeper tissues. In this case, M1, M3, and M18 are the M protein types that have been found to be associated with invasiveness in Strep pyogenes.

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  • Jun 20, 2010
    Quiz Created by
    Nycpm2013
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Most common causative agent of the system infection, infective...
Which causes the systemic infection post-viral lobar pneumonia
Most common causative agent of the systemic infection, bacteremia and...
Are Strep Gram positive or negative?
Cystitis is
Staphylococcus
Beta-hemolytic
Systemic infection of S. aureus due to highly absorbent tampons
S. aureus resistant to methicillin (Methicillin Resistant Staph Aureus...
In pustulent or necrotic tissues due to S. aureus infection, what...
Yellow-golden colored, round shape
S. aureus
Which is the most common causative agent of the systemic infection,...
Causes the sytemic infection Staphylococcal Colitis (Necrotizing...
Staph epidermidis is part of normal flora
The urease produced by ________ may mediate host pathogenesis.
S. aureus 
Can contaminated food carry S. aureus?
Which organism infects both normal and damaged heart valves?
For dry foot lesions caused by S. aureus, use
Staphylococcus
Most common causative agent of the systemic infection Osteomyelitis
Linezolid (Zyvox) and Synercid are two drugs that treat MRSA. How?
The following applies to ...
How are saprophyticus and epidermidis different from aureus in terms...
Staphylococcus
All of the following are localized infections produced by S. aureus...
Pyelonephritis is 
Streptolysin O (SLO)
Systemic infection caused by S. aureus in which inhalation can lead to...
Streptococci have what cell arrangement? 
Which is sub-grouped based on the Lancefield Groupings (A-H, K-M, O-V)...
Sugar fermentation and esculin hydrolysis are the...
S. aureus
Toxin A and B, which are exotoxins of S. aureus, are what kind of...
S. epidermidis systemic infections have what origin?
How are both Staph saprophyticus and Staph epidermidis different from...
Which staph can cause both pyelonephritis and cystitis?
Is Staph saprophyticus coagulase negative or positive?
Pyruria (Pus in the urine) is commonly due to which Staph?
Halophilic (halotolerant); will grow in presence of 7.5% NaCl
Topical treatment for S. aureus
This exists. 
Streptococcus pyogenes falls into which group
M. luteus is what type of species
Corynebacteria species are also known as
More drug resistant
Erythrogenic toxin of Strep pyogenes is a superantigen
Is Staph saprophyticus DNase positive or negative?
Which bacteria can be highly invasive?
Molecular mimicry seen in the hyaluronic capsule of ____________ makes...
Which Staph may infect the urinary tract of patients due to poor...
What is the primary habitat of Streptococci?
_________ have an oral and enteric clinical presenation and its...
P-V leukocidin associated with 
Which exotoxin of ...
Frank pathogen, as opposed to opportunistic commensal
Color of Staph epidermidis
Streptokinase of Strep pyogenes 
You can get antibody formation with which Streptolysin of...
Where is Toxin A preformed?
Strep mutans is what kind of strep?
Systemic infection caused by S. aureus that shows as an increased...
Staph epidermidis
Which of the following are sensitive to Novobiocin?
S. aureus causes
Nuclease of Strep pyogenes does this
S. mucilaginous is an example of what type of microorganism?
Toxin A of S. aureus causes
Which exotoxin of S. aureus is a superantigen?
Streptococci have what hemolytic properties
Which types of S. aureus produce exfoliatin?
This S. epidermidis virulence factor has adhesion to host tissue and...
In Strep pyogenes, there are at least how many different serotypes of...
Ingestion of pre-formed toxin
Staphylokinase opposes what virulance factor of S. aureus?
This should be suspected with any topical S. aureus infection of the...
Clumping factor associated with endocarditis as it adheres to heart...
It is not possible to carry S. aureus and be unaffected
In Strep pyogenes, certain M proteins resemble sarcolemmal membrane...
Strep pyogenes does not have hyaluronidase activity
Streptococci
What does beta lactamase lead to?
Which ...
Is Staph saphrophyticus Mannitol positive or negative?
Lancefield grouping scheme was developed for what purpose?
Streptococcus pyogenes colonizes which 2 areas?
Is Strep pyogenes hyaluronic acid capsule immunogenic?
Streptolysin O (SLO)  _______ in presence of oxygen
SLS
UTIs are systemic infections of which Staph?
Systemic infection associated with S. aureus that affects the bone...
Which bacteria are the most important bacteria, medically speaking?
The immunogenicity of SLO is important for which 2 medical conditions
This virulence factor of Strep. pyogenes causes the red rash of...
This tests for the susceptibility to erythrogenic toxin of Strep...
Nuclease of strep pyogenes is a spreading factor because it
Staph saprophyticus is resistant to which antibiotic?
What do mutant penicillin-binding proteins result in?
Which 2 medically important Streptococci cannot be classified by "C"...
Streptococcus pyogenes has which hemolysis pattern?
Streptococcus pyogenes
Strep anginosus is what kind of strep?
Which exotoxin of S. aureus is most common?
Catalyzes the formation of thrombin which converts fibrinogen to...
In scalded skin syndrome (Ritter's disease), isolates lysogenized by...
Attachment to epithelial cells via hemagglutinins and other cell...
This affects only abnormal or damaged heart valves, and prosthetic...
Causes tissue necrosis and acts like a detergent
Which drug is not appropriate for treating MRSA/VISA/GISA
Staph saprophyticus does which type of hemolysis?
For moist foot lesions caused by S. aureus, use
In the dick test, after injection, if a red rash appears, the person
S. aureus has sphingomyelinase activity thanks to this
This S. aureus virulence factor procures nutrients and decreases pus...
Staphylococcal Colitis (Necrotizing enterocolitis is a superinfection...
Strep pyogenes uses _______ aka streptodornase as a virulence factor
Streptococcus pyogenes is sensitive to which antibiotic?
Staph epidermidis
Which antiobiotic is used to treat Staph epidermidis?
Is S. saprophyticus urease positive or negative?
Is S. aureus part of normal flora?
Staph epidermidis (pick two)
This Staph has multiple drug resistances including methicillin,...
S. aureus and S. epidermidis have two which systemic infections in...
Which system infection caused by S. aureus is often follows orthopedic...
Describe M protein of Strep pyogenes (choose two)
Which 2 virulence factors causes Streptococcus pyogenes to have a...
This binds to the Fc portion of IgG to block complement binding and...
Strep pyogenes - in strains associated with tissue necrosis...
Causes Staph. pseudomembranous enterocolitis (superinfection)
Staph epidermidis is resistant which antibiotics? (Choose as many as...
In Strep pyogenes, this virulence factor is associated with increased...
Which is not an important spreading factor for S. aureus?
This is motile
S. aureus has P-V leukocidin that works with this detergent
Virulence factor of S. aureus that activates plasmin leading to the...
Leukotoxin is also known as 
Enterotoxins from S. aureus have these three characteristics
Which virulence factor of Strep pyogenes is essential for...
Which is not associated with pitted keratolysis
If the S. aureus isolate is sensitive, what treatment would you use to...
S. aureus and S. epidermidis have which 2 virulence factors in common?
In Strep pyogenes, which M protein types are associated with...
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