Microbiology Chapter 11 Test Bank

Correct Answer: A

Rationale: The correct answer is A: Candidiasis. In infants, a thick white deposit on the oral mucosa and tongue is indicative of oral thrush, which is caused by the yeast fungus Candida. Infants are particularly susceptible to Candidiasis due to their developing immune systems and use of antibiotics. Favus (B) is a chronic fungal infection of the scalp caused by Trichophyton schoenleinii, typically not seen in infants. Epidermophytosis (C) refers to superficial fungal infections of the skin caused by dermatophytes, not commonly found in the oral cavity of infants. Actinomycosis (D) is a bacterial infection caused by Actinomyces species, not a fungal infection.

Correct Answer: A

Rationale: The correct answer is A: Tuberculin. The Mantoux test involves injecting tuberculin, a protein derivative of Mycobacterium tuberculosis, under the skin to check for a delayed hypersensitivity reaction in individuals exposed to TB. B: BCG vaccine is a live attenuated vaccine used for TB prevention, not for diagnostic testing. C: DTP vaccine is for diphtheria, tetanus, and pertussis, not TB. D: Tularinum is not a standard immunobiological preparation used for TB testing. Therefore, A is the correct choice for the Mantoux test.

Correct Answer: A

Rationale: The correct answer is A: IgG. Anti-tetanus gamma globulin is produced by hyperimmunization, leading to a high concentration of specific antibodies, predominantly IgG. IgG is the most abundant immunoglobulin in the blood and provides long-term immunity against tetanus. IgA is mainly found in mucosal areas, not in gamma globulin preparations. IgM is the first antibody produced in response to an infection and is not the prevailing class in this preparation. IgE is associated with allergic reactions and parasitic infections, not with anti-tetanus immunity.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Hospital-acquired infections can be caused by a variety of bacteria commonly found in healthcare settings. Staphylococcus aureus is a common cause of surgical site infections. Escherichia coli can cause urinary tract infections. Klebsiella pneumoniae is associated with pneumonia and bloodstream infections. Therefore, all three bacteria are frequently implicated in hospital-acquired infections due to their prevalence and ability to cause different types of infections in healthcare settings. Thus, the correct answer is D, as all of the listed bacteria are commonly associated with hospital-acquired infections.

Correct Answer: C

Rationale: The correct answer is C: Rickettsia. Rickettsia is a host-dependent bacterium because it requires living cells of a host organism to survive and replicate. This bacterium is an obligate intracellular pathogen, meaning it cannot grow outside of a host cell. A: Mycoplasma and B: Ureaplasma are not host-dependent as they can grow and reproduce in cell-free environments due to possessing their own unique cell wall structures. D: Micrococcus is a free-living bacterium that can survive and reproduce independently without relying on a host organism.