Infection caused by the genus Candida can be successfully treated with:

Correct Answer: C

Rationale: Step-by-step rationale for why choice C (Nystatin) is the correct answer: 1. Nystatin is an antifungal medication specifically effective against Candida infections. 2. Candida is a type of fungus, not a bacteria targeted by penicillins (choice A) or cephalosporins (choice B). 3. Nystatin works by disrupting the fungal cell membrane, leading to its death. 4. Choice D (None of the above) is incorrect as Nystatin is a suitable treatment option for Candida 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.

Correct Answer: D

Rationale: The correct answer is D: Middlebrook's medium. This medium is specifically designed for the growth of Mycobacterium tuberculosis due to its low concentration of malachite green, which inhibits the growth of other bacteria but not Mycobacterium species. Middlebrook's medium also contains various nutrients that support the growth of Mycobacterium tuberculosis. A: Middlebrook's medium is the correct answer, not incorrect. B: Heart infusion broth is a general-purpose medium, not specific for Mycobacterium tuberculosis. C: MacConkey agar is selective for gram-negative bacteria and would not support the growth of Mycobacterium tuberculosis. In summary, Middlebrook's medium is the ideal choice for cultivating Mycobacterium tuberculosis due to its specific formulation that promotes the growth of this pathogen while inhibiting other bacteria.

Correct Answer: B

Rationale: The correct answer is B: antitoxin. Antitoxin is the specific antidote to botulinum toxin as it helps neutralize the toxin in the body. Sodium bicarbonate (A) is used to treat acidosis, pralidoxime (C) is used for organophosphate poisoning, and naloxone (D) is used for opioid overdose. Antitoxin directly targets and counteracts the botulinum toxin, making it the appropriate antidote in cases of botulism.

Correct Answer: A

Rationale: The correct answer is A: incidence. Incidence refers to the number of new cases of a disease occurring within a specific time period in relation to the healthy population. It helps in understanding the risk of developing the disease. Prevalence (B) is the total number of existing cases at a given point in time. Virulence (C) is the severity of the disease once contracted. Mortality (D) refers to the number of deaths due to the disease, not the new cases. Therefore, the correct term for new cases is incidence.