Correct Answer: D

Rationale: The correct answer is D: BCG vaccination. BCG vaccination is recommended for individuals with a negative Mantoux test result, especially in countries where tuberculosis is prevalent. This vaccination can help provide protection against tuberculosis. Choice A is incorrect because repeating the Mantoux test in a month is unnecessary since the boy already had a negative reaction. Choice B is incorrect as serodiagnosis of tuberculosis is not the first-line approach for diagnosis, especially in this scenario. Choice C is incorrect because urgent isolation is not necessary based solely on the Mantoux test result. Isolation is typically reserved for individuals with active tuberculosis.

Correct Answer: C

Rationale: The correct answer is C: Escherichia coli. E. coli is a gram-negative bacterium, which means it has an outer membrane containing lipopolysaccharides (LPS), also known as endotoxins. Endotoxins are released when the bacterium is destroyed, causing an inflammatory response. Streptococcus pneumoniae (choice A) is a gram-positive bacterium and does not produce endotoxins. Clostridium tetani (choice B) produces exotoxins, not endotoxins. Staphylococcus aureus (choice D) is also a gram-positive bacterium and does not produce endotoxins. In summary, E. coli is the correct answer because it is a gram-negative bacterium that produces endotoxins, while the other choices are gram-positive bacteria that do not produce endotoxins.

Correct Answer: A

Rationale: The correct answer is A: Continuous infection with long incubation period. Fudrjant fern of injection is a term used to describe an infection that is continuously present in the body after being introduced through injection. The long incubation period refers to the time between the injection and when symptoms of the infection become apparent. This choice is correct as it accurately describes the characteristics of fudrjant fern of injection. Choice B is incorrect because chronic infections typically have a long duration, not a short incubation period. Choice C is incorrect as immediate infections would not have a long incubation period. Choice D is incorrect because a 'sleeping' infection implies a dormant state, not continuous presence in the body as seen in fudrjant fern of injection.

Correct Answer: B

Rationale: Certainly! The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic environments due to their ability to switch between utilizing oxygen for respiration in aerobic conditions and utilizing fermentation or anaerobic respiration in anaerobic conditions. This flexibility allows them to thrive in diverse environments. Explanation for incorrect choices: A: Obligate aerobes require oxygen for respiration and cannot survive in anaerobic environments. C: Obligate anaerobes can only survive in the absence of oxygen and would not thrive in aerobic conditions. D: Microaerophiles require low levels of oxygen to grow and are not as versatile in adapting to varying oxygen levels compared to facultative anaerobes.

Correct Answer: C

Rationale: The correct answer is C because "Infectious disease" is a combination of both a clinical term (A) and a term expressing the possibility of developing certain symptoms in an infection (B). Infectious diseases are illnesses caused by pathogenic microorganisms, such as bacteria, viruses, parasites, or fungi, that can spread directly or indirectly from person to person. Therefore, the term encompasses both the clinical aspect of the disease and the potential symptoms that may manifest in an infected individual. Choices A and B alone do not fully capture the comprehensive definition of infectious disease, making C the correct answer. Choice D is incorrect as there is a correct answer in this case.