Molecular characterization of extended-spectrum beta-lactamase producing escherichia coli. (c2014)

Abstract

The increasing prevalence of Extended-spectrum Beta-lactamases in many countries including Lebanon, a country with a dynamic population represents a challenge for the healthcare systems. Given the fact that the incidence of ESBL-producing bacteria is increasing worldwide and the number of associated nosocomial infections is also escalating. This study aimed at determining the increasing prevalence of ESBLs in a tertiary care center in Lebanon, identifying the possible associated risk factors and medical complications, assessing the clonal relatedness among the isolated strains, and identifying the most common resistance genes. Screening for ESBL producing E. coli was performed on patients admitted to the ICU for lower GI/ urological surgical procedures. Among 75 patients, there were 12 patients who were carrying ESBL-producing E. coli on admission and 10 patients who acquired the colonization after the surgery. By collecting 3 rectal swabs from each patient, 60 isolates were confirmed as ESBL producing and analyzed indiscriminately before the unblinding of patients’information. These isolates belonged to 31 PFGE type and each clonal group included strains isolated from the same patient at different stages of hospitalization, which indicated that the strains are clonally diverse among the different patients. Three clonal groups represented an upsetting exception whereby each group included strains isolated from 3 different patients and patient to patient transmission was suspected in the ICU unit. In addition, ESBL isolates showed alarming broad antibiotic resistance profiles and PCR results detected CTX-M-I group as the predominant ESBL type. Associated risk factors include age above sixty-one, diabetes, and recurrent urinary tract infections which might be predisposing or associated with the colonization of this pathogen. These results agree with previously published studies in Lebanon and worldwide and highlight the increasing incidence and dissemination of these pathogens in the hospital and community setting and draws attention to the broadening of resistance among ESBLs whereby therapy alternatives are becoming scarce.