Among patients infected with Shiga toxin–producing Escherichia coli during the 2011 outbreak in Germany, azithromycin significantly decreased colonization with the organism, allowing patients to return to normal work and social activities instead of being quarantined, according to a report in the March 14 JAMA.
Most recommendations discourage the use of antibiotics in cases of STEC infection because this therapy is believed to increase the risk of hemolytic uremia syndrome (HUS), said Dr. Martin Nitschke of the University Hospital of Schleswig-Holstein, Lübeck, Germany, and his associates.
However, in the context of severe neurologic involvement or persistent HUS despite plasmapheresis therapy, treatment with eculizumab is advised. And because eculizumab enhances susceptibility to meningococcal infection, concomitant preventive therapy with azithromycin also is recommended.
Dr. Nitschke and his colleagues compared the rates of persistent STEC colonization in 22 patients who received azithromycin in this fashion vs. 43 control subjects who did not receive azithromycin. All 65 study subjects were hospitalized at their medical center and were followed for up to 45 days.
At 3 weeks, the rate of STEC carriage was 32% in the patients who received azithromycin, compared with 84% in the control group. At 4 weeks, the rates were 5% and 81%, respectively, the investigators said (JAMA 2012;307:1046-52).
By 5 weeks, all patients who received azithromycin were clear of STEC organisms and remained STEC negative thereafter. In contrast, 25 of 43 control subjects (58%) still carried STEC and continued to do so for more than 50 days; some control subjects remained STEC carriers for more than 160 days.
Patients who are colonized with STEC are considered infective, and their social and work activities are legally restricted by German health authorities, "posing a high psychological and socioeconmic burden," Dr. Nitschke and his associates said.
No cases of HUS developed in association with azithromycin therapy.
When the researchers noted the rapid clearance of STEC colonization with azithromycin and the lack of toxicity, they offered the antibiotic to an additional 15 patients who had persistent colonization. Seven of these patients achieved rapid decolonization without any clinical sequelae; four achieved later decolonization at 43-68 days, also without clinical sequelae; and four were lost to follow-up.
No patients in any of the study groups developed HUS or required rehospitalization during 6 more months of follow-up.
These findings indicate that azithromycin "might be considered a potentially effective and safe antibiotic for the treatment of enteroaggregative STEC infection," Dr. Nitschke and his colleagues said.
Their study was limited in that it was a single-center assessment with a "relatively small" sample size, and patients were not randomly assigned to treatments. The results, therefore, warrant confirmation in larger studies, they added.
This study received no industry funding. Dr. Nitschke reported ties to Novartis, Genzyme, and Roche, and his associates reported ties to numerous industry sources.