A Preliminary Occurrence of Extended-Spectrum and AmpC Beta-Lactamases in Clinical Isolates of EnteropathogenicEscherichia coliin Najaf, Iraq

Extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase producing enteropathogenic Escherichia coli (EPEC) have become an important clinical problem due to their resistance to multiple antibiotics. The purpose of this study was to evaluate the multi-drug resistant (MDR) and β-lactamases producing EPEC isolated from children with diarrhea. Twenty two EPEC strains were gathered from another study performed from September to November 2009. Antibiotic susceptibilities against 20 antibiotics determined by the agar disk diffusion according to the protocol recommended by Clinical and Laboratory Standards Institute guidelines (CLSI). Phenotypic confirmatory tests carried out for screening of ESBLs and AmpC β-lactamase. The isolates subjected to PCR assays with specific primers for bla -genes ( bla SHV , bla TEM , bla CTX-M and bla OXA , bla PER , bla VEB and bla GES ). Only 22 (3.4%) EPEC isolates recovered from clinical infections. MDR rate in EPEC was 90.9%. Phenotypic confirmatory tests showed that 13.6% and 20.0% of isolates were ESBL and AmpC β-lactamase producers, respectively. Among the EPEC isolates, percent recovery of bla SHV , bla TEM , bla CTX-M and bla OXA genes was 100%, 81.8%, 77.3% and 9.1%, respectively. Only 2 (9.1%) isolates had bla AmpC gene and none of the isolates carried bla PER , bla VEB and bla GES genes. The results of our study showed that the ESBLs were common among EPEC isolates. Such high dissemination of ESBLs is a serious problem for public health and therefore, it is necessary to seek a program for monitoring ESBLs in Najaf hospitals. This study is the first report on the presence of the bla -genes in EPEC isolates in Najaf.