Aim: We intended to find out the diversity of EPEC isolates among asymptomatic or diarrheal children in Iran using ribotyping.Background: Enteropathogenic Escherichia coli (EPEC) is responsible for gastroenteritis especially in young children.Patients and methods: A total of 39 EPEC collected strains were serotyped and the presence of virulence genes as well as EAF plasmid among the strains was studied. Adherence assay was also performed. Clonal diversity of the isolates was investigated using ribotyping.Results: Of 39 studied strains of E. coli, 6 serogroups of EPEC were represented. The presence of the stx gene was ascertained in 7 isolates and the eaeA, eaeB and bfpA genes were harbored by 5, 3 and 1 strains, respectively. Ribotyping yielded 9 different clusters.Conclusion: According to our results there was not a significant correlation between the results of serotyping and those of ribotyping. However, different serotypes of E. coli may belong to the same ribotype clusters and vice versa.

Background and Objectives: Enteropathogenic Escherichia coli (EPEC) strains can be detected by serogrouping and the presence of enterocyte attaching- effacing (eae) gene. Most EPEC strains belong to a certain O antigenic group. Locus of enterocyte effacement (LEE) Pathogenicity Island contains the eae gene and secretory proteins (ESPs) that introduce the attaching-effacing lesion. LEE inserted in tRNA genes include the SelC, PheU and PheV sites. The aim of the present study was to genetically characterize EPEC strains isolated from children with diarrhea.Materials and Methods: Serogrouping was performed by EPEC antisera in 321 E. coli isolates. The presence of eae, stx, espB, and eaf genes and detection of insertion sites of LEE was done by PCR using specific primers.Results: Seventeen (5.3%) isolates belonging to 7 EPEC serogroups were identified among the whole material and all carried the eae gene. None of the 321 isolates showed presence of stx gene indicating that all 17 isolates classified as EPEC by O serogrouping did not belong to the enterohaemorrhagic E. coli (EHEC) group. Of these, 8(53%) isolates carried the eaf and 16 (94.1%) carried the espB gene. The insertion sites of LEE in serogrouped isolates were selC (in 6 isolates), pheU (in 7 isolates) and pheV (in 2 isolates). The insertion site in 2 isolates was not determined by PCR.Conclusion: Serogrouping and detection of the eae gene showed to be reliable for detection of EPEC strains. No Shigatoxin- producing E. coli (STEC) strain was found among the isolates. Detection of the insertion site of LEE showed that selC, pheU or PheV are insertion sites of LEE in the EPEC strains.

Background: Diarrhoeal diseases remain one of the leading causes of childhood morbidity and mortality in most developing countries, with enteropathogenic Escherichia coli (EPEC). Typical and atypical EPEC strains differ in several characteristics. Typical EPEC, a leading cause of infantile diarrhea in developing countries, is rare in industrialized countries, where atypical EPEC seems to be a more important cause of diarrhea. Typical and atypical EPEC also differ in genetic characteristics, serotypes, and virulence properties. The aim of study was survey of prevalence of typical and atypical Enteropathogenic Escherichia coli obtained from children with diarrhea.Methods: In the present study, we collected 272 stool samples related to children with diarrhea that were referred to Division of Microbiology, School of Public Health, Tehran University of Medical Sciences. E.coli isolates, Enteropathogenic Escherichia coli isolates, were identified by using standard microbiological and biochemical tests. Subsequently, for identification of atypical and typical EPEC was survey of presence of eae and stx and bfp A genes by PCR method.Findings: Out of 272 samples, 156 isolates were identified as E.coli. 10 isolates identified as EPEC each of them was atypical.Conclusion: High prevalence EPEC in children is a threat to children in our country. The previous research has shown that atypical EPEC, a leading cause of infantile diarrhea, is more in industrialized countries but in present study, all EPEC were atypical.

The present study was conducted to detect the occurrence, serotype, genotype, phylogenetic relationship and antimicrobial resistance pattern of STEC from healthy goats of West Bengal, India. From the 125 faecal samples collected from healthy goats, 245 isolates were identified as Escherichia coli. The E. coli harbouring any gene for Shiga toxins (stx1/stx2) was detected in 36 (14.7%) of the 245 E. coli isolates. These STEC strains belonged to 22 different serogroups (O2, O5, O20, O21, O22, O25, O41, O44, O45, O60, O71, O76, O84, O85, O87, O91, O103, O112, O113, O120, O156, and O158) and three were untypeable. The stx1 and stx2 was detected in 26 (72.2%) and 21 (58.3%) of Shiga toxin producing-E. coli (STEC) isolates, respectively. Further, E. coli harbouring eaeA only (Enteropathogenic E. coli) and ehxA was detected in 22 (61.1%) and 28 (77.7%) isolates, respectively. Whereas the saa was present in 8 (22.2%) E. coli isolates. The subtyping of the 26 E. coli strains possessing stx1 showed that 73.% (19.26) of these isolates were positive for stx1C subtype. Of the 21 isolates with the stx2 gene, 42.8% (9.21) were positive for stx2C, and 38.1% (8.21) were positive for stx2d gene. The phylogenetic analysis of STEC strains after RAPD reveals eight major clusters. However, no serogroup specific cluster was observed. Resistance was observed most frequently to erythromycin (80.5%), amikacin (52.7%), cephalothin (50%), kanamycin (41.6%), neomycin (36.1%) and gentamycin (36.1%) and less frequently to norfloxacin (2.7%), enrofloxacin (2.7%), and ciprofloxacin (2.7%). Multidrug resistance was observed in eleven STEC isolates.