Molecular Identification of ESBLs Genes (blaTEM, blaSHV and blaCTX) among Non-fermenting Gram-negative Bacteria Isolated from Hospitalized Patients in Mazandaran Province, Iran

Production of beta-lactamase enzymes by bacteria, especially Extended-spectrum β-lactamases (ESBLs) is one of the major problems worldwide. ESBLs are mostly located on bacterial plasmids and it is recognized that SHV, TEM, and CTX-M are prevailing among them. The aim of this study was to determine the ability to produce ESBLs genes based on molecular method among non-fermenting Gram-negative bacteria (Pseudomonas aeruginosa and Acinetobacter baumannii) isolated from hospitalized patients in Mazandaran province, Iran.

In this cross-sectional descriptive study, 81 non-fermenting bacterial isolates were collected. The isolates were tested for antibiotic susceptibility according to CLSI guidelines. Molecular identification of blaSHV, blaTEM, and blaCTX-M genes was performed using specific primers and polymerase chain reaction (PCR) method.

Of 81 non-fermentative bacteria isolated, 49 (60.5%) isolates of A. baumannii were detected and 32 (39.5%) isolates were confirmed as P. aeruginosa. The prevalence of identified genes in these isolates was as follows: 26% blaSHV, 19% blaTEM, and 12% blaCTX-M in P. aeruginosa and 11% blaTEM, 8% blaCTX-M, and 4% blaSHV in A. baumannii.

ESBL positive strains of P. aeruginosa and A. baumannii are increasingly found in hospital isolates. Their high ability to pass resistant genes to other clinical strains requires their quick detection in clinical laboratories.