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

This study aimed to investigate the frequency and molecular epidemiology of class A ESBLs producing Enteroinvasive Escherichia coli (EIEC) isolates among patients with diarrhea. Background: Antibiotic resistance is widespread among diarrheagenic Escherichia coli (DEC) in developing countries. Information regarding Extended-Spectrum β-Lactamases (ESBLs) in diarrheagenic pathogens should be considered in clinical management when an optimal treatment is required. Methods: A total of 581 stool samples were collected from patients with diarrhea in Ahvaz, Iran. PCR was used for the presence of the ipaH gene to confirm EIEC strains. The antibiotic resistance pattern of all EIEC isolates was determined by the disk diffusion method. EIEC isolates were screened for class A β-lactamase genes. Genotyping of harboring β-lactamase genes was performed by Multi-Locus VNTR Analysis (MLVA). Results: Among 13 EIEC isolates, 9 isolates (69.2%) were found ESBL positive by double-disk synergy test (DDST) and PCR. Furthermore, blaCTX-M-15 and blaCTX-M-1 genes were detected in 77.8% (n=7) and 44.5% (n=4) of the blaCTX-M-1 group. On the other hand, the blaTEM-1 gene was detected in 66.6% (n=6). None of the isolates had blaSHV-1, blaKPC, or blaGES genes. Six MLVA genotypes were identified. Conclusion: The current study revealed that the presence of ESBLs genes mediates the resistance of EIEC isolates to the majority of antibiotics in this region. The presence of ESBLs genes in different MLVA types showed that one specific clone was not responsible for spreading the EIEC isolates.