Patients treated with azithromycin experienced a reduced length of E. coli infection compared with untreated patients, according to study results.
Researchers evaluated 65 participants infected with Shiga toxin-producing enteroaggregative E. coli (STEC) at a center in Lübeck, Germany from May 15 to July 26, 2011. Patients received either orally-administered azithromycin (n=22) or no antibiotic treatment (n=43), and investigators monitored their symptoms for a mean of 39.3 days after onset. Among the participants, all 22 in the antibiotic group and 15 in the untreated group also had hemolytic uremic syndrome (HUS).
Within the treated group, one participant (4.5%) carried the infection for more than 28 days (95% CI, 0%-13.3%) compared with 35 patients (81.4%) in the untreated group (95% CI, 69.8%-93.0%). By day 35, all participants in the treated group tested negative for STEC, and experienced no recurrence during the study. After 42 days, 57.7% of the untreated group remained STEC carriers (95% CI, 40.5%-75.0%). Following rapid results from the treated group, researchers also administered azithromycin to 15 initially untreated participants for 3 days, after which they all produced STEC-negative stool samples.
“According to existing recommendations, antibiotic treatment of STEC infection is discouraged because this therapy might increase the risk of HUS development,” researchers wrote. “In this study, we found no evidence that azithromycin worsened the clinical course with regard to local or systemic symptoms in patients with severe HUS. Our findings suggest that among patients with STEC infection, exposure to azithromycin is associated with a lower frequency of long-term STEC carriage.” They also wrote these results warrant testing of the treatment against other strains of STEC and future clinical trials.