Objective: Shiga toxin-producing
E. coli
(STEC) is a pathogenic
E. coli that may cause hemolytic uremic
syndrome (HUS) after diarrheal disease through Shiga toxins. Management of the patients with STEC infection
is different from that of other diarrheal diseases due to increase in frequency of HUS after antibiotic
administration. Few studies were conducted in Iran and epidemiology of STEC remains obscure; this
necessitates examination of stools especially in young children for this bacterium.
Methods: We determined the frequency of STEC in 947
E. coli strains isolated from diarrheal stools of
children less than 14 years in Tehran with conventional culture methods and multiplex-PCR via determining
the STX1 and STX2 genes, between October 2008 and September 2009. We also evaluated the association
between stool exam findings and presence of STEC.
Findings:Twenty seven (2.8%) of
E. coli isolates were positive for STX1 or STX2 genes, most of which
occurred in spring (P<0.05). There was no significant association between STEC positivity and stool exam
findings. Eighteen out of 27 (66.7%) Shiga toxin positive samples were isolated from males and the rest from
females. The most common STX-positive diarrheal samples showed loose consistency (P<0.017).
Conclusion: Although the low frequency of STEC in our population indicates that it is not a major problem in
our population, STEC should be regarded as an important infection because of its severe consequences.
Further studies with greater sample size are needed to confirm our results.
