Chapter 21 Microbiology Final Summer 2009

Lysosome is an organelle found in cells that contains enzymes responsible for breaking down various substances. Peptidoglycan is a component of bacterial cell walls. Lysosomes are known to hydrolyze or break down peptidoglycan, aiding in the degradation and elimination of bacteria. This process is important for the immune system to defend against bacterial infections.

Oil and sweat are secretions of the body that can serve as nutrients for microorganisms. Microorganisms, such as bacteria and fungi, can use the oil and sweat on the skin as a food source, allowing them to survive and multiply. This is why it is important to maintain good hygiene practices, such as regular bathing and washing, to remove excess oil and sweat from the body and reduce the availability of nutrients for microorganisms.

The stratum corneum is the outermost layer of the skin and is composed of dead skin cells that are filled with keratin. Keratin is a protein that helps to provide strength and protection to the skin. It is also responsible for the waterproofing properties of the skin.

Mucous membranes are the correct answer because they are responsible for releasing slippery fluid to the outside of the body. Mucous membranes line various parts of the body, such as the respiratory tract, digestive tract, and reproductive system. They secrete mucus, which helps to lubricate and protect these areas from friction and pathogens. The slippery fluid produced by mucous membranes aids in the smooth movement of substances, such as food and air, through these body systems.

The matrix material of mucous membranes is made of hyaluronic acid.

Diptheroids are a type of bacteria that are part of the normal microbiota of the skin. They are characterized by their appearance, which resembles "fat rods". These bacteria are typically harmless and can be found on the skin of healthy individuals. They play a role in maintaining the balance of the skin microbiota and can help protect against colonization by harmful bacteria.

Selenium is a heavy metal that can be found in soil.

Cornybacterium xerosis is a type of bacteria that is commonly found on dry skin. This bacteria thrives in environments with low moisture levels, making dry skin an ideal habitat. It is important to note that cornybacterium xerosis is a normal part of the skin's microbiota and does not typically cause any harm. However, in certain cases, it can contribute to skin infections or other dermatological issues. Therefore, maintaining proper skincare routines and keeping the skin moisturized can help prevent the overgrowth of cornybacterium xerosis and maintain healthy skin.

Exanthem is another term used to describe a local infection with a skin rash. This term is commonly used in the medical field to refer to a rash that appears on the skin as a result of an infection or an allergic reaction. It is characterized by redness, inflammation, and sometimes blisters or bumps on the skin. Exanthem is often caused by viruses or bacteria and can be contagious.

A vesicle that is 1cm or less lies between the dermis and epidermis layers of the skin.

Subcutaneous skin lesions are characterized by being located beneath the skin. These lesions are typically filled with pus, which is a thick, yellowish fluid that consists of dead white blood cells, bacteria, and tissue debris. Pus is formed as a result of the body's immune response to an infection or injury. It helps to isolate and eliminate the source of infection or foreign material from the body. Therefore, it is expected that subcutaneous skin lesions would be filled with pus.

Staphylococcus aureus is the most pathogenic strain of staphylococcus and is coagulase positive. Coagulase is an enzyme produced by some strains of staphylococcus, and the presence of coagulase can help differentiate between pathogenic and non-pathogenic strains. Staphylococcus aureus is known for causing a range of infections in humans, including skin and soft tissue infections, respiratory infections, and bloodstream infections. The positive coagulase test indicates that this strain has the ability to form clots, which can help it evade the immune system and establish infection.

Leukocidin is a toxin that specifically targets and kills white blood cells (WBCs). This toxin is produced by certain bacteria and can damage or destroy WBCs, impairing the immune response and making the body more susceptible to infections.

Staph aureus has a "super" antigen that causes "cytokine storms". This means that the antigen produced by Staph aureus is extremely potent and can trigger an excessive immune response in the body, leading to the release of large amounts of cytokines. These cytokines can cause severe inflammation and damage to tissues, resulting in the development of cytokine storms.

Impetigo is a skin infection that is spread by autoinoculation, meaning that the infection can spread from one area of the body to another through scratching or touching the affected area. It is characterized by the presence of non-bacillus sores, which are red, itchy, and may ooze fluid or form a crust. Impetigo is commonly seen in children and can be caused by bacteria such as Staphylococcus aureus or Streptococcus pyogenes. Treatment usually involves antibiotics and keeping the affected area clean to prevent further spread of the infection.

A sty is a type of folliculitis that affects the hair follicle of an eyelash. Folliculitis is an inflammation or infection of the hair follicle, which can be caused by bacteria or other factors. In the case of a sty, the hair follicle on the eyelash becomes infected, leading to redness, swelling, and discomfort.

Hemolysins are substances that can cause the destruction of red blood cells (RBCs). The statement suggests that hemolysins are not specific to RBCs, meaning that they can also affect other types of cells. This implies that hemolysins have the ability to cause damage to a variety of cell types, not just RBCs.

The correct answer is "endotoxin A" because endotoxin A is a virulence factor produced by invasive streptococcal infections. It is a potent superantigen that can cause excessive immune system activation and contribute to the severity of the infection.

Pseudomonas aeruginosa is associated with hot tubs and spas.

Pseudomonas aeruginosa is a type of bacteria that can grow in flower water and mop water.

In some areas, the incidence of Buruli ulcer is higher than the incidence of leprosy and TB. This means that there are more reported cases of Buruli ulcer compared to the number of reported cases of leprosy and TB in those specific areas. It is possible that the prevalence of Buruli ulcer is higher due to various factors such as environmental conditions or specific populations at risk.

Imiquimod is a medication used in the treatment of papilloma viruses. It works by stimulating interferon production. Interferons are proteins that play a crucial role in the body's immune response against viral infections. By stimulating interferon production, imiquimod helps to boost the immune system's ability to fight off the papilloma viruses.

Warts are tubular atypical growths that can occur on the skin. While they are not typically considered cancerous, they are a type of abnormal cell growth. Warts are caused by the human papillomavirus (HPV) and can appear on various parts of the body. They are usually harmless and can often go away on their own, but treatment may be necessary in some cases.

Isotretinoin is a treatment specifically used for nodular cystic acne. This type of acne is severe and characterized by large, painful, inflamed nodules or cysts that can cause scarring. Isotretinoin works by reducing the production of oil in the skin, preventing the clogging of pores, and reducing inflammation. It is typically prescribed when other acne treatments have failed to provide satisfactory results.

Sebum channels in commedonal acne are blocked, leading to the formation of blackheads on the skin.

The correct answer is inflammatory and testosterone. The prevalence of acne is higher in males than females due to the higher production of inflammatory and testosterone hormones. These hormones can increase sebum production and cause the enlargement of sebaceous glands, leading to the development of acne.

The poxvirus was eradicated by vaccination in 1978.

The correct answer is monkey pox. Monkey pox is a rare viral disease that primarily affects animals, including monkeys, but can also be transmitted to humans. In this case, the outbreak of monkey pox in the US originated from pet prairie dogs that were housed with Gambian giant rats. This highlights the potential for zoonotic diseases, where an infection can jump from animals to humans, and the importance of proper handling and containment of exotic pets to prevent the spread of such diseases.

Chicken pox is caused by a virus called varicella-zoster virus. It leads to the formation of pus-filled vesicles on the face, throat, and torso. These vesicles typically appear after 2 weeks of infection and last for about 3-4 days. Therefore, the correct answer is "chicken pox, torso". The repetition of "chicken pox and torso" and "chicken pox torso" in the answer options reinforces the idea that chicken pox primarily affects the torso area.

The correct answer is "attenuated." Attenuated vaccines contain weakened forms of the virus or bacteria that cause the disease. In the case of breakthrough varicella, it refers to a vaccine that provides immunity against varicella (chickenpox) by using a weakened form of the varicella-zoster virus. This type of vaccine is designed to stimulate an immune response without causing the full-blown disease.

The reactivation of latent HHV-3 (Herpes simplex virus type 3) releases viruses that move along peripheral nerves to the skin, causing shingles.

HSV-1, also known as the herpes simplex virus type 1, has the ability to remain dormant or latent in the trigeminal nerve ganglia. The trigeminal nerve is responsible for transmitting sensory information from the face to the brain. This means that after an initial infection, the virus can hide in the trigeminal nerve ganglia and stay inactive for long periods of time. It can reactivate later, causing recurrent outbreaks of cold sores or other symptoms associated with HSV-1.

Herpes encephalitis is a viral infection that affects the brain. It is caused by the herpes simplex virus, which spreads to the brain and causes inflammation. This condition can lead to severe neurological symptoms and can be life-threatening if not treated promptly. Therefore, herpes encephalitis fits the given description of a virus that spreads to the brain.

Rubella is a viral infection that can cause congenital rubella syndrome when contracted during pregnancy, especially within the first trimester. This syndrome can result in severe fetal damage, including hearing loss, heart defects, cataracts, and intellectual disabilities. Rubella is highly contagious and can be prevented through vaccination.

Roseola is a viral infection caused by the herpes virus 6 (HHV-6) and 7 (HHV-7). It is a common childhood illness characterized by a high fever followed by a rash. The virus is usually transmitted through respiratory secretions and can spread easily among young children. The fever typically lasts for a few days and once it subsides, a pinkish-red rash appears on the body. Roseola is usually a mild and self-limiting illness, and most children recover fully without any complications.

Dermatomycosis is a fungal infection of the skin, hair, or nails. It is commonly referred to as tineas or ringworm. Both terms are used interchangeably to describe the same condition.

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Candidiasis may result from the suppression of competing bacteria by antibiotics. Antibiotics are designed to kill harmful bacteria, but they can also kill beneficial bacteria that help keep the growth of other microorganisms, such as Candida (the fungus that causes candidiasis), in check. When the competing bacteria are suppressed, Candida can overgrow and cause an infection. This is why candidiasis is often seen as a side effect of antibiotic use.

Thrush is an infection of the mucous membranes of the mouth.

Conjunctivitis is the inflammation of the conjunctiva, which is the thin, clear tissue that covers the white part of the eye and lines the inside of the eyelid. This condition is commonly known as pink eye and can be caused by allergies, viruses, or bacteria. Symptoms may include redness, itching, watery discharge, and crusty eyelids. Conjunctivitis is usually not serious and can be easily treated with medication or home remedies.

Keratitis is the correct answer because it refers to the inflammation of the cornea. The term "keratitis" is derived from the Greek words "kerato" meaning cornea and "itis" meaning inflammation. When the cornea becomes inflamed, it can cause symptoms such as eye redness, pain, blurred vision, and sensitivity to light. Various factors can lead to keratitis, including infections, injuries, allergies, and underlying conditions. Prompt diagnosis and treatment are essential to prevent complications and preserve vision.

Chlamydia trachomatis is a bacterium that causes a common sexually transmitted infection. However, it can also be spread through other means, such as contaminated water. In this case, the question suggests that Chlamydia trachomatis can be spread through swimming pool water with low chlorine levels. This is because chlorine is commonly used as a disinfectant in swimming pools to kill bacteria and other microorganisms. Therefore, if the chlorine levels are low, it may not effectively kill the Chlamydia trachomatis bacteria, allowing it to be transmitted to individuals who come into contact with the contaminated water.

Herpetic keratitis is the most common cause of infectious blindness in the US. This condition is caused by the herpes simplex virus, which can infect the cornea of the eye and lead to inflammation and scarring. If left untreated, herpetic keratitis can cause vision loss and even blindness. Therefore, it is important to diagnose and treat this condition promptly to prevent permanent damage to the eyes.

Acanthamoeba keratitis is a type of eye infection caused by the Acanthamoeba parasite. This parasite is commonly found in water and soil, and can enter the eye through the use of unsanitary contact lenses. People who do not properly clean and disinfect their contact lenses or use contaminated water to clean them are at a higher risk of developing Acanthamoeba keratitis. This infection can cause severe eye pain, redness, blurred vision, and sensitivity to light. Prompt treatment is necessary to prevent further damage to the eye.

Propionibacterium acnes is a type of bacterium that is commonly found in hair follicles. It is an anaerobe, meaning it can survive and thrive in environments with little to no oxygen. This bacterium is known to play a role in the development of acne, as it can cause inflammation and infection within the hair follicles. Therefore, the correct answer is "propioni."

Impetigo of the newborn, also known as Ritter's syndrome, can resemble a burn if not correctly diagnosed. This condition is characterized by widespread skin blisters and erosions, which can be mistaken for burn injuries. It is important to accurately identify this condition to ensure appropriate treatment and prevent unnecessary interventions for burn management.

Stretolysins are substances that dissolve clots.

Grisofulvin is a medication that is taken orally and it specifically affects keratin producing areas. This means that it targets and inhibits the growth of fungi that infect the skin, hair, and nails, as these areas produce keratin. Grisofulvin works by binding to the microtubules in the fungal cells, disrupting their function and preventing their replication. By targeting keratin producing areas, it helps to eliminate fungal infections in these specific areas of the body.