Extended Spectrum β-Lactamase-Producing Strains of Escherichia coli in Hospitalized Children in Isfahan, Iran

Background: Beta-lactam antibiotics such as long-spectrum cephalosporins and carbapenems are the empirical treatment against urinary tract infections (UTIs). The common mechanism of resistance to B-lactamas in Escherichia coli is producing of ESBLs. Objectives: The aims of this study was evaluation of the susceptibility of the ESBL-producing E. coli strains to ordinarily used antibiotics and to detect the presence of the four common ESBL genes: blaTEM, blaOXA, blaCTX-M, and blaSHV using multiplex PCR method. Materials and Methods: In a retrospective cross sectional study conducted between 2012 and 2013, out of145 strains of E. coli were isolated from hospitalized children with UTIs. Susceptibility test was performed by disc diffusion method. All isolates were also tested for ESBL by the standard CLSI double disk diffusion method, using cefotaxime / clavulanic acid and ceftazidime/clavulanic acid disks. Multiplex PCR was performed for detect of blaCTX-MIV, blaOXA, blaTEM, and blaSHV genes. Results: From 145 strains of E. coli, 51(35.2%) and 61(42.1%) isolates were resistance to ceftazidime and cefotaxime, respectively. ESBL production was noted in 59 (40.7%) strains. The amplification of β-lactamase genes showed the presence of blaCTX-M like genes in 22 (37.9%) strains, blaTEM in 42 (72.4%), blaSHV in 7 (11.9%) and blaOXA in 23 (39%) of the total 58 strains of E. coli. Conclusions: Our data showed that, the high prevalence of beta-lactamase genes among isolates, and it. Our findings may provide usefu