During a genital examination, the nurse notices that a male patient has clusters of small vesicles on the glans, surrounded by erythema. The nurse recognizes that these lesions are:

Correct Answer: C

Rationale: The correct answer is C: Genital herpes. Genital herpes presents as clusters of small vesicles on the glans surrounded by erythema. This is a classic presentation of genital herpes infection caused by herpes simplex virus. Peyronie disease (A) is characterized by penile curvature. Genital warts (B) are caused by human papillomavirus and appear as flesh-colored growths. Syphilitic chancre (D) is a painless ulcer seen in primary syphilis, not vesicles. In this case, the presence of vesicles and erythema points towards genital herpes as the most likely diagnosis.

Correct Answer: C

Rationale: The correct answer is C: Steven-Johnson syndrome from Trimethoprim/Sulfamethoxazole. Steven-Johnson syndrome is a severe and potentially life-threatening adverse reaction characterized by rash, blistering, and mucosal involvement. Once a patient experiences Steven-Johnson syndrome from a specific drug like Trimethoprim/Sulfamethoxazole, they should never be given that drug again due to the high risk of recurrence and the severity of the reaction. This is known as a contraindication, making it unsafe to administer the drug in the future. A, B, and D are incorrect because GI upset from Clarithromycin, skin rash from Ampicillin, and Clostridium difficile superinfection from Ciprofloxacin, while unpleasant, are not typically considered contraindications for future use of the same drug. These adverse reactions can often be managed with dose adjustments, alternative medications, or supportive care without ruling out the drug entirely

Correct Answer: A

Rationale: Step-by-step rationale: 1. Cloxacillin is a beta-lactam antibiotic effective against Staphylococci. 2. Streptococci are not within the spectrum of activity for Cloxacillin. 3. Gonococci are also not susceptible to Cloxacillin. 4. Therefore, the correct answer is A (Streptococci), as Cloxacillin is indicated only for Staphylococcal infections. Summary: Choice A is correct because Cloxacillin is effective against Staphylococci. Choices B and C are incorrect because Cloxacillin is not indicated for Gonococci or all of the organisms mentioned.

Correct Answer: C

Rationale: The correct answer is C: Trimethoprim/Sulfamethoxazole. This combination is the first-line treatment for Pneumocystis carinii pneumonia in patients with HIV-AIDS due to its efficacy against the organism. Trimethoprim inhibits bacterial folic acid synthesis, while sulfamethoxazole inhibits bacterial dihydrofolic acid formation. These drugs work synergistically to target different steps in the folic acid synthesis pathway of Pneumocystis carinii, leading to its effective eradication. Metronidazole (A) is used for anaerobic bacterial infections, Carbenicillin (B) is a penicillin derivative mainly used for Gram-negative bacteria, and Penicillin G (D) is not effective against Pneumocystis carinii.

Correct Answer: A

Rationale: The correct answer is A: Two nucleoside reverse transcriptase inhibitors (NRTIs) + one protease inhibitor (PI). This regimen is typically reserved for advanced cases of AIDS or repeated treatment failures due to its potent antiviral effects. NRTIs inhibit viral replication by interfering with the HIV enzyme reverse transcriptase, while PIs inhibit the enzyme protease, essential for viral maturation. Combining these two classes of drugs provides a strong barrier against HIV resistance. Other choices (B, C, D) are less effective in advanced cases as they do not provide the same level of dual inhibition necessary to combat resistant strains and advanced disease progression.