Select the most appropriate first-line antimicrobial therapy for each of the following patient scenarios.
- A 32-year-old woman with a 2-day history of dysuria, urinary frequency, and suprapubic tenderness. She is otherwise healthy and not pregnant.Nitrofurantoin
- A 25-year-old man presenting with an expanding, annular erythematous rash with central clearing on his thigh 10 days after a hiking trip.Doxycycline
- A 40-year-old man with rapidly progressive, painful, erythematous swelling of his hand 12 hours after sustaining a deep puncture wound from a domestic cat.Amoxicillin-clavulanate
- A 19-year-old college student with fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and a positive rapid antigen detection test.Oral penicillin V
- A 65-year-old man with COPD presenting with fever, increased purulent sputum, and a new lobar infiltrate on chest radiograph, requiring outpatient treatment.Levofloxacin
Answer
The scenarios match as follows: uncomplicated cystitis with Nitrofurantoin; early localized Lyme disease with Doxycycline; infected cat bite with Amoxicillin-clavulanate; Group A streptococcal pharyngitis with Oral penicillin V; and community-acquired pneumonia with comorbidities with Levofloxacin.
Each presentation requires a specific antimicrobial choice: Nitrofurantoin concentrates in the urine for cystitis; Doxycycline targets Borrelia; Amoxicillin-clavulanate covers Pasteurella and anaerobes in bites; Penicillin V is targeted for Group A Strep; and Levofloxacin provides expanded coverage for community-acquired pneumonia in patients with comorbidities.
Step-by-Step Solution
Key Concept
Selecting appropriate first-line antimicrobial therapy based on clinical presentation and likely pathogens.