title: Fecal Colonization with Extended-Spectrum Beta-Lactamase and AmpC-Producing Escherichia coli.
abstract: Background. Extended-spectrum β-lactamases (ESβLs) and AmpC β-lactamases cause β-lactam resistance in Escherichia coli. Fecal colonization by ESβL- and/or AmpC-positive E. coli is a source of nosocomial infections. Methods. In order to investigate inpatient fecal colonization by ESβLs and AmpC, antibiotic sensitivity tests were conducted and minimum inhibitory concentrations (MICs) were determined using the disk diffusion method and E-test, respectively. Characterization of ESβL and AmpC was performed using E-test strips, and a set of PCRs and DNA sequence analyses were used to characterize the ESβL and AmpC genes. Results. The whole collection of E. coli isolates (n = 50) was sensitive to imipenem, tigecycline, colistin, and fosfomycin, while 26% of the isolates showed reduced susceptibility to ceftazidime (MIC ≥ 4 μg/mL). ESβL was phenotypically identified in 26% (13/50) of cases, while AmpC activity was detected in two ESβL-producing E. coli isolates. All ESβL-producing E. coli were positive for the CTX-M gene, eleven isolates carried bla CTX-M-15, and two isolates carried bla CTX-M-14 gene. Two CTX-M-positive E. coli isolates carried bla CMY-2. Conclusions. The alimentary tract is a significant reservoir for ESβL- and/or AmpC-producing E. coli, which may lead to nosocomial infection.
authors.affiliation: Department of Pharmaceutics, Microbiology Division, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia; Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt.
authors.forename: Mohamed H
authors.identifier: 0000-0001-9868-0355
authors.initials: MH
authors.lastname: Al-Agamy
authors.affiliation: Microbiology and Immunology Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt.
authors.forename: Taghrid S
authors.initials: TS
authors.lastname: El Mahdy
authors.affiliation: Department of Pharmaceutics, Microbiology Division, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
authors.forename: Atef M
authors.initials: AM
authors.lastname: Shibl
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification* / Q000378:metabolism; D005243:Feces / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases