American Board of Internal Medicine (ABIM) Certification Practice Exam

Which antibiotics are typically prescribed for diarrhea caused by Vibrio?

1. Doxycycline × 1 dose

2. Azithromycin × 1 dose

3. Fluoroquinolone × 3 days; azithromycin × 3 days

4. Rifaximin × 7 days

The correct answer is: Fluoroquinolone × 3 days; azithromycin × 3 days

When treating diarrhea caused by Vibrio species, particularly Vibrio cholerae, the recommended antibiotics usually include azithromycin and fluoroquinolones, with azithromycin often being favored for its effectiveness and lower resistance development. Choosing fluoroquinolones for a duration of three days is appropriate as they are effective against Vibrio and help shorten the duration of symptoms when used appropriately. However, combining this with a three-day course of azithromycin is also supported, particularly in cases of antibiotic-resistant strains or in certain populations, such as children or pregnant individuals, where azithromycin may be preferred. This combination approach not only targets the underlying infection but also contributes to management strategies, particularly in acute settings where rapid recovery is beneficial. The dual therapy may be particularly relevant in endemic areas or during outbreaks where antibiotic resistance is a concern. While other options like doxycycline and single-dose regimens may also be effective, they do not cover the breadth of scenarios encountered with Vibrio-mediated diarrhea as comprehensively as the combination of fluoroquinolone and azithromycin over a longer duration. Antibiotic resistance patterns and emerging strains are always important considerations in treatment choices as well, making the combination more resilient against variations in the pathogens present.