Which of the following is the most appropriate choice of treating aspergillosis?

Correct Answer: B

Rationale: The correct choice for treating aspergillosis is B: Amphotericin B. It is the most appropriate due to its broad antifungal spectrum, including activity against Aspergillus species. Amphotericin B is often considered the first-line treatment for invasive aspergillosis. Terbinafine (A) is more commonly used for dermatophyte infections, not aspergillosis. Flucytosine (C) is mainly used for Cryptococcal infections. Itraconazole (D) may have some activity against Aspergillus, but it is generally less effective than Amphotericin B for invasive cases.

Correct Answer: C

Rationale: The correct answer is C: Valacyclovir. Valacyclovir is an antiviral medication commonly used to treat herpes simplex virus infections. It is a prodrug of acyclovir, which inhibits viral replication by targeting the viral DNA polymerase enzyme. Valacyclovir is effective in reducing the severity and duration of genital herpes outbreaks. A: Zanamivir is an antiviral medication used to treat and prevent influenza virus infections, not herpes simplex virus infections. B: Lamivudine is an antiretroviral medication used to treat HIV and hepatitis B infections, not herpes simplex virus infections. D: Cidofovir is an antiviral medication used to treat cytomegalovirus (CMV) infections, not herpes simplex virus infections. In summary, Valacyclovir is the most appropriate choice for treating genital herpes simplex virus infection due to its effectiveness in inhibiting viral replication and reducing the severity of outbreaks.

Correct Answer: A

Rationale: The correct answer is A: Nalidixic acid + Nitrofurantoin. This combination does not exhibit supraadditive synergism because both drugs have similar mechanisms of action targeting bacterial DNA synthesis. In contrast, the other choices involve drug combinations with different mechanisms of action which result in synergistic effects, making them more effective against a wider range of microbes. Amoxicillin + Clavulanic acid work together to inhibit bacterial cell wall synthesis, Pyrimethamine + Sulfadoxine target folate biosynthesis pathways, and Sulfamethoxazole + Trimethoprim inhibit sequential steps in bacterial folic acid synthesis. Therefore, A is the correct answer as the combination lacks synergy due to overlapping mechanisms of action.

Correct Answer: A

Rationale: The correct answer is A: Streptomycin. Streptomycin binds to the S12 ribosomal subunit, inhibiting protein synthesis in mycobacteria. It is effective against drug-resistant tuberculosis and is used as an injectable drug. Streptomycin is known to cause ototoxicity and nephrotoxicity as side effects. Choice B: Ethambutol inhibits cell wall synthesis in mycobacteria, not protein synthesis. Choice C: Isoniazid inhibits mycolic acid synthesis in the cell wall of mycobacteria. Choice D: Rifampicin inhibits RNA synthesis by binding to the beta subunit of bacterial RNA polymerase.

Correct Answer: A

Rationale: Rationale: 1. Caspofungin is the correct answer as it inhibits the synthesis of β1,3 glucan in fungal cell walls, leading to cell lysis and death. 2. Amphotericin B acts by binding to ergosterol in fungal cell membranes, disrupting membrane integrity (fungistatic). 3. Flucytosine is converted to 5-fluorouracil inside fungal cells, inhibiting DNA synthesis (fungistatic). 4. Ketoconazole inhibits ergosterol synthesis, disrupting membrane function (fungistatic).