Which of the following microorganisms can cause skin infections?

Correct Answer: B

Rationale: The correct answer is B: All are correct. Candida albicans can cause skin infections such as candidiasis. Staphylococcus aureus and Streptococcus pyogenes are common bacteria that can also cause skin infections. Therefore, choice B is correct as all three microorganisms listed can cause skin infections. Choices A, C, and D are incorrect because individually, each of the microorganisms listed can cause skin infections.

Correct Answer: D

Rationale: The correct answer is D because smallpox vaccination provides long-lasting immunity, often for a lifetime. Revaccination is not necessary as the initial vaccine confers sufficient protection. Choice A is incorrect because yearly revaccination is unnecessary and excessive. Choice B and C are also incorrect as there is no need for revaccination every second or third year. The key is to understand that smallpox vaccination typically provides lifelong immunity, making ongoing revaccination unnecessary.

Correct Answer: C

Rationale: The correct answer is C because plasmids do not encode essential bacterial properties. They are non-essential, extra-chromosomal DNA molecules that can replicate independently within bacterial cells. Plasmids mainly contain genes for antibiotic resistance, genetic transfer, and other specific functions. Choice A is correct as many plasmids do carry antibiotic resistance genes. Choice B is also accurate as plasmids are indeed smaller, circular, and exist outside the bacterial chromosome. Choice D is true as plasmids can facilitate bacterial conjugation, allowing the transfer of genetic material between bacteria.

Correct Answer: D

Rationale: The correct answer is D: Fungi do not stain in the gram staining method because they have a unique cell wall composition different from bacteria. Fungi have chitin in their cell walls, which is not easily stained by the gram staining process. This method primarily targets the peptidoglycan layer present in bacterial cell walls. Therefore, fungi will not take up the stain and will remain colorless. The other choices (A: Blue-purple, B: Red, C: Silver) are incorrect because they describe colors that are associated with staining results for bacteria, not fungi.

Correct Answer: D

Rationale: The correct answer is D: All are correct. Patients planned for treatment with monoclonal antibodies should be tested for HBV, HCV, and M. tuberculosis due to the risk of reactivation of these infections during treatment. HBV and HCV reactivation can lead to severe liver damage, while M. tuberculosis reactivation can cause serious respiratory complications. Testing for all three infections helps in identifying and managing any pre-existing infections to ensure patient safety during monoclonal antibody treatment. Choices A, B, and C are incorrect because each of these infections presents specific risks that need to be assessed before initiating monoclonal antibody therapy.