Match each clinical scenario with the most appropriate antimicrobial therapy or prophylaxis regimen.
- A 34-year-old man with untreated HIV (CD4 count 35 cells/mm³) who presents with visual floaters; fundoscopy reveals peripheral, yellowish-white retinal lesions with hemorrhage, sparing the macula.Oral valganciclovir
- A 48-year-old spelunker from the Ohio River Valley with mild fever, nonproductive cough, and palatal ulcers; tissue microscopy shows small yeast cells within macrophages.Oral itraconazole
- A 65-year-old man with a mechanical mitral valve replacement who is presenting for a routine dental extraction with gingival manipulation.Oral amoxicillin
- A 22-year-old pregnant woman (first trimester) who requires post-exposure prophylaxis after her roommate developed Neisseria meningitidis meningitis.Intramuscular ceftriaxone
Answer
Peripheral CMV retinitis requires oral valganciclovir. Mild-to-moderate histoplasmosis requires oral itraconazole. Endocarditis prophylaxis for a mechanical valve undergoing a dental procedure is oral amoxicillin. Meningococcal prophylaxis in a pregnant patient is intramuscular ceftriaxone.
Each correct pairing matches the clinical presentation to its optimal, guideline-concordant antimicrobial regimen, explicitly accounting for host variables such as pregnancy (necessitating ceftriaxone over ciprofloxacin) and lesion location (allowing oral valganciclovir over intravitreal therapy).
Step-by-Step Solution
Key Concept
Selection of first-line antimicrobial therapy and prophylaxis requires integration of the specific pathogen, disease severity, and unique host factors (such as pregnancy, immunosuppression, and prosthetic hardware).