microbiology basic and clinical principles test bank

Correct Answer: C

Rationale: The correct answer is C: young adults. Young adults are at a higher risk for sexually transmitted infections (STIs) due to factors such as engaging in risky sexual behaviors, lack of awareness, and inconsistent condom use. They are more likely to have multiple sexual partners and are less likely to seek regular STI screenings. Adolescents, while also at risk, may not make up almost half of all STI cases in the U.S. The elderly, on the other hand, are generally at a lower risk due to lower levels of sexual activity compared to young adults.

Correct Answer: B

Rationale: The correct answer is B: biofilms. Biofilms refer to complex communities of microorganisms that adhere to surfaces. They are characterized by a protective matrix that allows the microorganisms to communicate and cooperate. Colonies (A) typically refer to groups of a single species, not diverse communities. Biospheres (C) refer to the regions of the Earth where life exists, not specific microbial communities. Flora (D) generally refers to the plant life in a particular region, not microbial communities on surfaces.

Correct Answer: B

Rationale: Step-by-step rationale for why choice B (Tuberculin is introduced) is correct: 1. Tuberculin test helps identify individuals with latent TB infection. 2. Negative skin-allergic samples suggest absence of active TB. 3. Introducing tuberculin can help confirm latent TB infection. 4. Antibiotics are not prescribed for negative skin-allergic samples. 5. Vaccines are not administered for TB diagnosis. Summary: - Choice A is incorrect as antibiotics are not prescribed for negative skin-allergic samples. - Choice C is incorrect as vaccines are not used for TB diagnosis. - Choice D is incorrect as introducing tuberculin is the appropriate step in this scenario.

Correct Answer: C

Rationale: Correct Answer: C: Halophiles Rationale: 1. Halophiles are bacteria adapted to high salt environments. 2. They have specific mechanisms to tolerate high salt concentrations. 3. Acidophiles thrive in acidic conditions. 4. Thermophiles prefer high temperature environments. 5. Mesophiles grow best at moderate temperatures.

Correct Answer: D

Rationale: The correct answer is D: Propionibacterium acnes. This bacterium is not a fungus, but a common skin bacteria. Fungal vaginitis is typically caused by Candida albicans or other fungal species, not by bacteria like Escherichia coli, Streptococcus agalactiae, or Klebsiella oxytoca. Propionibacterium acnes is not associated with vaginal infections, making it the correct answer in this context.