Context The use of antibiotics for treatment of Escherichia
coli O157:H7 infection has become controversial since a recent small
study found that it may increase the risk of hemolytic uremic syndrome (HUS).
However, other larger studies have reported a protective effect or no association.
Objective To determine whether antibiotic therapy for E coli O157:H7 enteritis increases the risk of HUS.
Data Sources PubMed and MEDLINE computer searches were performed for studies published
from January 1983 to February 2001 using the key words hemolytic uremic syndrome, risk factor, antibiotics, and Escherichia coli O157:H7. Reference lists of relevant publications
were reviewed, and 12 experts in the field were contacted to identify additional
reports. No language restrictions were applied to the search.
Study Selection Studies were included if they reported a series of patients with documented E coli O157:H7 enteritis, some of whom developed HUS; had
clear definitions of HUS; and had adequate data delineating the relationship
between antibiotic therapy and the occurrence of HUS. Nine of the 26 identified
studies fulfilled these criteria.
Data Extraction Two authors (N.S. and A.S.) independently reviewed each report identified
by the searches and recorded predetermined information relevant to the inclusion
criteria. A pooled odds ratio was calculated using a fixed-effects model,
with assessment of heterogeneity among the studies.
Data Synthesis The pooled odds ratio was 1.15 (95% confidence interval, 0.79-1.68),
indicating that there does not appear to be an increased risk of HUS with
antibiotic treatment of E coli O157:H7 enteritis.
Incomplete reporting of data in individual studies precluded adjustment for
severity of illness.
Conclusion Our meta-analysis did not show a higher risk of HUS
associated with antibiotic administration. A randomized trial of
adequate power, with multiple distinct strains of E coli
O157:H7 represented, is needed to conclusively determine whether
antibiotic treatment of E coli
O157:H7 enteritis increases the risk of HUS.