Prevalence and Molecular Characterization of Plasmid-mediated Extended-Spectrum β-Lactamase Genes (balaTEM, blaCTX and blASHV) Among Urinary Escherichia coli Clinical Isolates in Mashhad, Iran

Abstract

Objective(s) Extended-spectrum beta-lactamase (ESBL) producing bacteria have an important role in nosocomial infections. Due to the limited availability of information about the molecular epidemiology of ESBL producing bacteria in Mashhad, we decided to investigate about TEM, CTX and SHV ESBLs among urinary <em>Escherichia coli</em> isolates in Mashhad, a city in northeast Iran. Materials and Methods One hundred and eleven clinical isolates of <em>E. coli</em> were diagnosed from hospitalized patients in 2009. After performing antibiogram and phenotypic confirmation test, polymerase chain reaction (PCR) was performed by bla_TEM, bla_SHV and bla_CTX primers and restriction digestion was carried out using PstI and TaqI (Fermentas-Lithuania) for confirmation. Results ESBL producers of E<em>. coli </em>isolates were 33.3%. Among 37 ESBL-producing isolates, 35 (94.6%), 21 (56.8%) and 5 (13.5%) were shown to have bla_CTX, bla_TEM and bla_SHV, genes respectively. Co-resistance to non-beta lactam antibiotics was observed more with ESBL producers (<em>P</em> < 0.05). Conclusion The results showed that the studied ESBL genes are found with high prevalence and among them bla_CTX is more widespread in urine <em>E. coli</em> isolates in Mashhad.