Evaluating the prevalence of Antibiotic resistance,ESBL genes, integrons, phylogenetic groups andMLVA profiles of Escherichia coli pathotypesisolated from patients with diarrhea and farmanimals in south-east of Iran

The aims of this study were to investigate the prevalence, antibiotic resistance, presence ofclass ۱ and ۲ in- tegrons, EXtended Spectrum β-Lactamases (ESBL) genes, phylogeneticgroup and epidemiological relationships of EPEC, ETEC and EHEC pathotypes isolated frompatients with diarrhea and farm animals in south east region of Iran. A total of ۶۷۱diarrheagenic E. coli (DEC) were collected from stool samples of ۳۹۵ patients with diarrheaand ۲۷۶ farm cattles and goats. Presence of EPEC, ETEC and EHEC were identified usingmultiplex-PCR em- ploying primers targeted the shiga toXin (stx), intimin (eae), bundle formingpili (bfp), and enterotoXins (lt and st) genes. The highest proportion of the patients (۶۴%) werechildren under age ۱–۱۵ year (p ≤ ۰.۰۵). Among the isolates, atypical EPEC was detected in۲۶ patients and ۱۴ animal stool samples, while typical EPEC was found in ۲ cattles. ETECisolates were detected in stools of ۱۳ patients and ۴ EHEC was identified in ۳ goats and onecattle. The isolates were checked for susceptibility to ۱۴ antibiotics. ۵۰% (n = ۱۳) of EPECand ۶۱.۵% (n =۸) of ETEC showed multi-drug resistance (MDR) profiles and one EPEC wasfound to be extensive drug resistant (XDR). In contrast, EHEC isolates were susceptible to the majority of antimicrobial agents. The MDR isolates were positive for blaTEM and blaCTX-MESBL genes and carried class ۱ integrons. Further study on the biofilm formation indicatedthat, ۳ out of ۴ EHEC isolates showed strong biofilm, while other pathotypes had eithermoderate, weak or no biofilm activity. Majority of EPEC isolates were belonged to phylogeneticgroup B۱, all except one ETEC were classified as phylogenetic group A and two EHEC werebelonged to phylogroup D, respectively. A multilocus variable tandem repeat analysis (MLVA)exhibited ۲۲ distinct patterns. In conclusion, MLVA data showed high clonal diversity.Presence of EHEC in animal origins pose public health concern in this region.

Keywords:

Antibiotic resistance , ESBL genes , Escherichia coli