Frequency and molecular epidemiology of class A ESBLs producing Enteroinvasive Escherichia coli (EIEC) isolates among patients with diarrhea

The aim of the present study was to evaluate the Multi-Locus VNTR Analysis (MLVA) method for genotyping of class A ?-lactamase genes harboring-EIEC strains isolated from patients with diarrhea.

Enteroinvasive E. coli (EIEC) is one of the most important causes of acute diarrhea in adults and children. The production of extended-spectrum ?-lactamases (ESBLs) enzymes among diarrheagenic E. coli (DEC) is one of the main mechanisms for resistance to antibiotics.

In this cross-sectional study, between September 2016 to August 2017, 569 stool samples were collected from patients with diarrhea referring to two hospitals, in Ahvaz, Iran. PCR was used for the presence of the ipaH gene to detected EIEC strains. The antibiotic resistance pattern of all EIEC isolates was determined by the disk diffusion method. EIEC isolates have been screened for class A ?-lactamase genes. Genotyping of harboring ?-lactamase genes were performed by MLVA.

Among 13 EIEC isolates, 9 isolates (69.2%) were found ESBL positive by DDST and PCR. Furthermore, blaCTX-M-15and blaCTX-M-1genes were detected in 77.8% (n=7) and 44.5% (n=4) of the blaCTX-M-1group. On the other hand, the blaTEM-1gene was detected in 66.6% (n=6).  None of the isolates had blaSHV-1, blaKPC, and blaGES genes. MLVA analysis revealed high genetic diversity among ESBLs genes-harboring isolates.

Our study emphasized the increasing role of ESBLs genes. The presence of ESBLs genes in different MLVA types showed that one specific clone was not responsible for spreading the EIEC isolates, and the dissemination of ESBLs in our isolates was due to the horizontal dissemination of mobile genetic elements in the unrelated isolates.