Oral aztreonam, a poorly absorbed yet effective therapy for bacterial diarrhea in US travelers to Mexico.

Abstract

To evaluate a poorly absorbed antimicrobial with in vitro activity against all major bacterial enteropathogens in oral therapy for bacterial diarrhea. One hundred ninety-one US students with diarrhea acquired in Mexico received 100 mg of aztreonam or matching placebo three times a day for 5 days. Stools were cultured for bacterial enteropathogens before and after therapy. We studied US students who acquired diarrhea in Mexico (travelers' diarrhea) in view of the high frequency of bacterial agents in this setting. We examined time of clinical recovery, treatment failures, adverse experiences, and microbiologic eradication from stool of the etiologic agent in subjects randomized to receive aztreonam or placebo. Aztreonam reduced the average duration of diarrhea compared with the placebo: for all cases, by 40 hours (P much less than .01); for those with enterotoxigenic Escherichia coli diarrhea, by 50 hours (P less than .01); for those with shigellosis, by 90 hours (P, not significant [small sample size]); for all bacterial agents, by 57 hours (P much less than .01). Clinical failures during the 5 days of therapy were seen in six patients (6%) receiving aztreonam and 25 (27%) receiving placebo (P less than .01). Pathogen eradication occurred in 95% of those receiving aztreonam and in 70% of those receiving the placebo (P less than .01). All bacterial enteropathogens were susceptible in vitro to aztreonam. The drug was well tolerated. Oral aztreonam, which is poorly absorbed, was well tolerated and was an effective therapy for bacterial diarrhea in US adults in Mexico.