Development of resistance to macrolide antibiotics in an AIDS patient treated with clarithromycin for Campylobacter jejuni diarrhea.

In an AIDS patient with diarrhea, identical isolates of Campylobacter jejuni susceptible and, later, resistant to macrolide antibiotics were isolated from feces before and after treatment with clarithromycin. Results of rRNA gene restriction analysis and serotyping suggest that development of resistance rather than simultaneous infection with a susceptible and a resistant strain was responsible for this phenomenon. This is the first report of in vivo development of resistance by Campylobacter jejuni in a patient treated with a macrolide for Campylobacter jejuni infection.