Mic Exam 3 Practice Questions

Some are Zoonotic, meaning they cause diseases in animals that can be transmitted to us

False. They differ in the types of diseases they cause

Bordetella pertussis causes whooping cough, also known as pertussis. This gram-negative bacilli is responsible for the contagious respiratory infection that affects the airways and causes severe coughing fits. It is transmitted through respiratory droplets and primarily affects infants and young children. The characteristic "whooping" sound occurs when the infected person tries to inhale after a coughing episode.

4 billion infections per year; 3 million deaths per year; More morbidity than any other bacterial group

It is spread by a flea bite… the Bacilli travel to lymph nodes… the infection results in swelling and pain… symptoms include high fever, chills, headache, nausea

H. influenzae is a bacterium that can cause various diseases, including respiratory tract infections, meningitis, and septicemia. It possesses endotoxins, which are molecules that can trigger inflammation in the body. When H. influenzae is present in the environment and enters the body, it can cause an immune response that leads to inflammation. Therefore, the statement that H. influenzae causes disease by simply being in the environment and sparking inflammation through endotoxin is true.

H. influenzae causes disease by simply being in the environment and sparking inflammation through endotoxin. This means that the mere presence of H. influenzae can lead to inflammation in the body, which can result in various diseases. Endotoxins are substances released by certain bacteria, including H. influenzae, that can trigger an inflammatory response in the host. Therefore, it is true that H. influenzae can cause disease by being in the environment and sparking inflammation through endotoxin.

Meningitis is caused by the encapsulated strain of H. influenzae. This bacterium has a protective capsule that allows it to evade the immune system and invade the meninges, which are the membranes surrounding the brain and spinal cord. Infection with the encapsulated strain of H. influenzae can lead to inflammation of the meninges, resulting in meningitis.

All of the listed symptoms, including double vision, dizziness, weakness, difficulty swallowing/speech, and respiratory failure/death, are symptoms associated with C. botulinum infection. This bacterium produces a neurotoxin that affects the nervous system, leading to muscle paralysis and various symptoms.

The statement is true because secondary pneumonia is indeed the biggest threat of whooping cough. Whooping cough, also known as pertussis, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. It primarily affects the respiratory system and can cause severe coughing fits, difficulty breathing, and a characteristic "whooping" sound. While whooping cough itself can be dangerous, secondary pneumonia is a common complication that can occur as a result of the infection. Pneumonia is a serious condition that can lead to further complications and even death, particularly in infants, young children, and individuals with weakened immune systems. Therefore, secondary pneumonia poses a significant threat in cases of whooping cough.

The anthrax capsule is composed of glutamic acid. This statement is true. Glutamic acid is a key component of the anthrax capsule, which is a protective layer surrounding the anthrax bacteria. The capsule helps the bacteria evade the immune system and survive in the host's body. By understanding the composition of the anthrax capsule, researchers can develop strategies to target and disrupt its formation, potentially leading to new treatments or preventive measures against anthrax infection.

Gram-negative bacilli are a diverse group of bacteria that can occupy various environmental niches. They are commonly found in the intestines, where they play a role in digestion and nutrient absorption. Additionally, they can colonize the respiratory tract, causing infections such as pneumonia. Gram-negative bacilli are also present in soil and water, where they contribute to the decomposition of organic matter and nutrient cycling. Therefore, the correct answer is "all of the above" as gram-negative bacilli can be found in intestines, respiratory tract, soil, and water.

They differe in Their ability to infect animals as well as humans

Unencapsulated strains of H. influenzae primarily cause local respiratory tract infections. These infections occur in the respiratory tract, such as the nose and throat, and can lead to symptoms like a sore throat, runny nose, and cough. Meningitis, systemic infections, and whooping cough are caused by other factors or pathogens, not specifically unencapsulated strains of H. influenzae.

Meningitis is a systemic infection caused by H. influenza. It is an inflammation of the protective membranes covering the brain and spinal cord. H. influenza is one of the common bacteria that can cause meningitis, especially in young children. Symptoms of meningitis include severe headache, fever, stiff neck, and sensitivity to light. If left untreated, meningitis can be life-threatening. Therefore, it is important to diagnose and treat it promptly.

The statement is true because B. pertussis, the bacterium that causes whooping cough, produces toxins that are released when infected cells die. These toxins are responsible for the symptoms of the disease, such as severe coughing fits, difficulty breathing, and the characteristic "whooping" sound. Therefore, for the symptoms to occur, the cells must die and release the toxins.

A protective antibody against the capsule is key for H. influenzae. The capsule of H. influenzae is a major virulence factor that helps the bacteria evade host immune responses. Antibodies against the capsule can neutralize the bacteria and prevent infection.

usually green or red and smells like grapes or juicy fruit gum

All contain endotoxin
Large variety of them also have exotoxins, enzymes capsules, fimbreae

It is Fastidious… this means it is difficult to grow. We must give it lots of growth factors

Serotype B (Hib) causes 95% of invasive disease, meaning the bacteria enters the bloodstream
Almost all Hib cases are in young children

Exotoxins are not produced by H. influenza. Exotoxins are toxic substances secreted by bacteria that can cause damage to host cells or tissues. While H. influenza produces other virulence factors such as fimbriae, capsule, and endotoxin, it does not produce exotoxins. Exotoxins are commonly produced by other bacteria such as Clostridium tetani (causing tetanus) or Corynebacterium diphtheriae (causing diphtheria).

Encapsulated strains produce the capsule
Unencapsulated strains don’t produce the capsule

Francisella tularemia can be transmitted through various routes, including infected tissue, inhalation, ingestion, and insect bites. This means that all of the options listed are correct routes of transmission for this bacterium.

Clostridium perfringens is a Gram-positive, spore-forming, rod-shaped bacterium. It is not a Gram-negative coccobacilli, which are typically small, oval-shaped bacteria that stain pink in the Gram stain. The other options listed, Haemophilus influenzae, Bordetella pertussis, Francisella tularemia, Brucella species, and Pasteurella multocida, are all Gram-negative coccobacilli.

Fimbriae for attachment to respiratory tract cells
Capsule is produced to prevent phagocytosis
Endotoxin which is part of ALL Gram-negative cells

The most important cause of nosocomial infections is E. coli. This bacterium is commonly found in the intestines of humans and animals and can cause various infections, especially in healthcare settings. It can be transmitted through contaminated food, water, or contact with infected individuals. E. coli infections can lead to urinary tract infections, pneumonia, bloodstream infections, and surgical site infections. Proper hygiene practices and infection control measures are important in preventing the spread of E. coli in healthcare settings.

The catarrhal stage is the first stage of whooping cough that occurs just as the bacteria start to die and release toxins. During this stage, symptoms such as a runny nose, sneezing, mild cough, and low-grade fever may appear. It is characterized by inflammation and increased mucus production in the respiratory tract. This stage typically lasts for 1-2 weeks before progressing to the paroxysmal stage, where severe coughing fits occur. After the catarrhal and paroxysmal stages, the convalescent stage follows, where the symptoms gradually decrease and the person starts to recover.

Clostridium perfringens is a Gram-positive anaerobic bacterium that can cause gas gangrene, food poisoning, and uterine infections. Gas gangrene is a severe infection that destroys muscle tissue and can lead to tissue death. Food poisoning caused by Clostridium perfringens occurs when contaminated food is consumed, leading to symptoms such as abdominal pain, diarrhea, and nausea. Uterine infections caused by this bacterium can occur after childbirth or during gynecological procedures. Clostridium botulinum causes botulism, a severe form of food poisoning, while Clostridium tetani causes tetanus. Clostridium difficile causes a serious infection called Clostridium difficile colitis.

pulmonary anthrax via inhalation of spores/antiphagocytic capsule/exotoxin … Cutaneous anthrax = localized/spores enter abrasions in skin … intestinal anthrax progresses to generalized toxemia, with fever, acute gastroenteritis, vomiting, bloody diarrhea

During the paroxysmal stage of whooping cough, one of the characteristic symptoms is mucous build-up in the lungs causing air blockage. This can lead to difficulty in breathing and can be a serious complication of the disease. It is important to recognize this stage and seek medical attention to prevent further complications and to ensure proper treatment.

The vibrio species have many similarities to Enterobacteriaceae, but not part of that family

Bordetella pertussis is the correct answer because it is a gram-negative bacilli that is difficult to grow, similar to H. influenzae. However, unlike H. influenzae, it does not specifically require X and V factors for growth.

It is non-invasive and It does all its damage where it lands in the respiratory tract

Nonencapsulated strains of Haemophilus influenzae are responsible for causing 90% of noninvasive respiratory tract infections. This means that the majority of respiratory infections caused by Haemophilus influenzae are caused by strains that do not have a protective capsule around them. The capsule helps bacteria evade the immune system, so nonencapsulated strains are more easily recognized and eliminated by the body's defenses.

Listeria monocytogenes is a common cause of septicemia and meningitis in both neonates and adults with impaired cell-mediated immunity. Listeria monocytogenes is a gram-positive bacterium that can be found in contaminated food, especially unpasteurized dairy products and deli meats. It can cross the placenta and cause infections in neonates, and it can also infect adults with weakened immune systems, such as those with HIV/AIDS or undergoing immunosuppressive therapy. This bacterium has the ability to invade and replicate within host cells, allowing it to evade the immune system and cause systemic infections like septicemia and meningitis.

Bordetella pertussis is not a Aerobic Gram-Positive Bacilli. This bacterium is a small, aerobic, Gram-negative coccobacillus that causes whooping cough or pertussis. Aerobic Gram-Positive Bacilli include corynebacterium diphtheriae, listeria monocytogenes, and bacillus anthracis.

these medically important species are named for the livestock they commonly come from

Antibodies against the capsule show that there are 6 different serotypes (a-f)

Pseudomonas aeruginosa is a gram-negative bacilli, so it is not the correct answer. Haemophilus influenzae, Bordetella pertussis, Francisella tularemia, and Pasturella multocida are all gram-negative bacilli.

Bordetella pertussis produces exotoxins, which are toxic substances secreted by the bacteria that can damage host cells and tissues. These exotoxins play a crucial role in the pathogenesis of pertussis (whooping cough) by causing damage to the respiratory tract and impairing the immune response. On the other hand, the main difference in virulence factors with H. influenzae is that B. pertussis does not have fimbrae or endotoxins. Fimbrae are hair-like structures that allow bacteria to attach to host cells, while endotoxins are lipopolysaccharides found in the outer membrane of Gram-negative bacteria that can cause inflammation and other harmful effects.

The correct answer is "pore-forming exotoxin." This is because all the other options listed (Pertussis toxin, Adenylate Cyclase Toxin, dermonecrotic Toxin, and tracheal cytotoxin) are exotoxins produced by B. pertussis. Exotoxins are proteins secreted by bacteria that can cause damage to host cells. Pore-forming exotoxins, on the other hand, create pores in the host cell membrane, leading to cell lysis.

The clinical syndrome of Franciscella tularensis caused by the ingestion of contaminated meat or water is typhoidal. This form of tularemia is characterized by symptoms such as high fever, headache, body aches, and gastrointestinal symptoms. It can also involve the lymph nodes, liver, and spleen. Unlike other forms of tularemia, the typhoidal form does not typically present with ulceration or involvement of the eyes or lungs.

The given answer is correct because all of the statements about diphtheria toxin are true. Diphtheria toxin is an enzyme that removes the ADP-ribose from NAD+ and transfers it to Elongation Factor II, making it an ADP-ribosylating exotoxin. This action of the toxin stops protein synthesis in the mammalian host cell, leading to the death of the host cell. Therefore, all of the above statements are true.

i. This is the MOST contagious stage since many bacteria still alive in respiratory tract and all the coughing and sneezing spread live bacteria easily to other children

there is an increase in cAMP. Increased cAMP causes loss of water from cells giving rise to watery diarrhea, fever, cramps

Ampicillin is not one of the best drugs active against almost 100 percent of H. influenzae strains. This is because H. influenzae has developed resistance to ampicillin over time, making it less effective against the bacteria. Therefore, while azithromycin, fluoroquinolones, and cephalosporin are all effective drugs against H. influenzae, ampicillin is not.

Bacillus food poisoning usually occurs because heat-resistant endospores survive cooking or pasteurization and then germinate and multiply when the food is inadequately refrigerated.

just a note: Tetracycline is the drug of choice when treating the disease

Penicillin is very effective, which is rare for gram-negative bacteria

The Shigella species is primarily spread through the oral route, typically through the ingestion of contaminated food or water. It is not typically spread through the bloodstream. The other statements are true about the Shigella species: it is acid stable, only a small number of live bacteria are needed for infection, and its endotoxin can cause inflammation.

Extra-intestinal E. coli refers to strains of E. coli that can cause infections outside of the intestines. These infections can include urinary tract infections, septicemia (bloodstream infection), and neonatal meningitis. This group of E. coli is able to cause these infections by invading and colonizing tissues outside of the intestines, leading to various clinical manifestations.

Cellulitis occurs in people that are bitten by infected animals

It is an Extracellular pathogen, does not invade into cells

At around 2 years of age, children begin to make their own antibodies to sugars and develop their own protection. Before this age, infants rely on antibodies passed on from their mothers through breast milk or during pregnancy. As their immune system matures, children gradually start producing their own antibodies, which help fight against infections and provide immunity. This process is an important milestone in the development of a child's immune system.

The correct answer is pertussis and Adenylate Cyclase Toxin. Both of these exotoxins produced by B. pertussis have the ability to increase cAMP levels.

(>2,000,000 per year). The key term here is acquired in the U.S., this does not count travelers diarrhea. Contaminated Food or Water is major source, and poultry account for 50% of infections

It has no effect on the disease

especially rabbits

LF = lethal factor = Zn++ dependent protease that induces cytokines … EF = adenylate cyclase

10% mortality if untreated. It is usually transmitted by primary inhalation, secondary spread from other forms.

Listeria monocytogenes is the only G+ bacterium with an endotoxin. Endotoxins are lipopolysaccharides found in the outer membrane of Gram-negative bacteria, but Listeria monocytogenes is a Gram-positive bacterium. However, it possesses a unique lipoteichoic acid that acts as an endotoxin-like molecule, allowing it to induce similar immune responses as endotoxins. Therefore, among the given options, Listeria monocytogenes is the only G+ bacterium that exhibits endotoxin-like properties.

Endotoxin is a virulence factor produced by H. influenzae that helps respiratory tract colonization by blocking cilia clearance and inducing inflammation at the site of infection. Endotoxin is a component of the bacterial cell wall and is released when the bacteria are damaged or destroyed. It activates the immune system and triggers an inflammatory response, leading to the recruitment of immune cells to the site of infection. This inflammation can impair the function of cilia, which are hair-like structures that help to clear mucus and debris from the respiratory tract, allowing the bacteria to colonize and persist in the respiratory tract.

You see an ulcer at the site of inoculation, is commonly seen in hunters that kill rabbits and skin them. This would be the form seen from insect bite as well

People on antacids show an increased risk for infection by s. typhi because antacids reduce the acidity in the stomach, which is an important defense mechanism against pathogens. S. typhi is a bacterium that causes typhoid fever and is typically transmitted through contaminated food and water. The lower stomach acidity caused by antacids can allow s. typhi to survive and multiply, increasing the risk of infection.

Clostridium botulinum is a bacterium that produces neurotoxins known as botulinum toxins. These toxins are responsible for causing botulism, a severe form of food poisoning. The question asks about the number of immunologically distinct neurotoxins produced by Clostridium botulinum. The correct answer is 8. This means that there are 8 different types of botulinum toxins produced by this bacterium, each with its own distinct immunological properties. These toxins can cause paralysis by blocking the release of acetylcholine, a neurotransmitter, at the neuromuscular junction.

Gentamicin is (it’s a bactericidal antibiotic)

Recall that not all enterics produce exotoxins

McDonalds, Jack in the Box, Nebraska hamburger plant… 20,000 cases per year… less than 100 bacilli ingested can cause disease so it’s easy to get