Characterization of diarrheagenic Escherichia coli strains associated with diarrhea in children, Khouzestan, Iran

Abstract

Introduction: Diarrheagenic Escherichia coli (DEC) is a major etiologic agent among the pathogens that cause diarrhea in children.

Methodology: To investigate the presence and pathotypes of DEC in children under five years of age, living in the province of Khouzestan, Iran. 208 diarrhea stool samples were screened by multiplex-PCR. The isolated DEC isolates were investigated for resistance to various antimicrobials including the production of extended-spectrum beta-lactamases (ESBLs) and phylogenetic groups were determined.

Results: DEC isolates were identified in 54 (26%) diarrhea samples, and 4 (7%) cases contained two DEC pathotypes. DEC isolated included 35 (16.8%) enteroaggregative E. coli (EAEC), ten (4.8%) enteropathogenic E. coli (EPEC), six (2.9%) enteroinvasive E. coli (EIEC), six (2.9%) enterotoxigenic E. coli (ETEC) and one (0.48%) LEE-positive EAEC. Shiga-toxin producing E. coli (STEC) was not identified in any diarrheal samples. The most prevalent resistance was observed with ceftazidime (88%), followed by ceftizoxime (83%) and ceftriaxone (71%). The majority of isolates (> 75%) were sensitive to Imipenem, ciprofloxacin, and amikacin. More than 65% of the pathogenic isolates showed a multidrug-resistant phenotype. ESBL-producing strains was observed in 79.3% of all DEC isolates. Phylogenetic group B2 was the most predominant group with a frequency of 44.8%. A significant association was observed between the B2 phylogenetic group and the DEC isolates (P < 0.05).

Conclusions: Overall, our findings highlight the importance of the role of DEC isolates in the etiology of diarrhea in children in Iran. The progressive increase in antimicrobial resistance among DEC isolates makes it imperative to implement policies to control the spread of resistant bacteria.

Keywords: Diarrheagenic Escherichia coli; ESBL; antimicrobial resistance; diarrhea; phylogenetic group.