Prevalence and Molecular Characterization of Ampicillin-Resistant Enterobacteriaceae Isolated from Traditional Egyptian Domiati Cheese
Abstract:The aim of this study was to address the prevalence and the molecular characteristics of antibiotic-resistant enteric bacteria isolated from one of the most popular types of Egyptian cheese. A total of 215 ampicillin-resistant enterobacterial isolates were obtained from 80 samples of Domiati cheese, and they were screened by PCR for a large pool of antibiotic resistance markers, including extended-spectrum β-lactamases (ESBLs), class 1 and class 2 integrons, and plasmid-mediated quinolone resistance genes. It was determined that the most frequent mechanism of ampicillin resistance was from a TEM-1–type β-lactamase. As well, SHV β-lactamases, including SHV-1, SHV-25, and SHV-26, showed a high prevalence, and two novel SHV β-lactamases, SHV-110 and SHV-111, were identified. Type CTX-M-14, OXY-1, OXA-1, and CMY-4 β-lactamases were also detected in a few isolates. In addition, a novel AmpC β-lactamase was detected that was designated CMY-41. Sequencing results of class 1 integrons revealed that the uncommon aminoglycoside resistance gene cassette aadA22 was found for the first time in an Escherichia coli strain. The other class 1 integrons harbored various common gene cassettes, including aadA1, aadA1a, aadA2, aadA12, dfr5, dfr7, dfr12, and dfr15. The only isolate that carried a class 2 integron contained dfrA1, sat2, and aadA1. Plasmid-mediated quinolone resistance determinants qnrS and qnrB showed a low prevalence. This study provides meaningful data on high antimicrobial resistance contained in Domiati cheese samples and reports for the first time the presence of β-lactamases, plasmid-mediated quinolone resistance, and integrons in isolates from food of Egyptian animal origin.
Document Type: Research Article
Affiliations: 1: Laboratory of Food Microbiology and Hygiene, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan 2: Laboratory of Food Microbiology and Hygiene, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan;, Email: firstname.lastname@example.org
Publication date: 2009-03-01
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