Beta-lactam resistant bacteria, which are commonly resident in tertiary hospitals, have emerged as a worldwide health problem because of ready-to-eat vegetable intake. We aimed to characterize the genes that provide resistance to beta-lactam antibiotics in Enterobacteriaceae, isolated from five commercial salad brands for
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Beta-lactam resistant bacteria, which are commonly resident in tertiary hospitals, have emerged as a worldwide health problem because of ready-to-eat vegetable intake. We aimed to characterize the genes that provide resistance to beta-lactam antibiotics in Enterobacteriaceae, isolated from five commercial salad brands for human consumption in Mexico City. In total, twenty-five samples were collected, grown in blood agar plates, and the bacteria were biochemistry identified and antimicrobial susceptibility testing was done. The carried family genes were identified by endpoint PCR and the specific genes were confirmed with whole genome sequencing (WGS) by Next Generation Sequencing (NGS). Twelve positive cultures were identified and their microbiological distribution was as follows: 8.3% for
Enterobacter aerogene (
n = 1), 8.3% for
Serratia fonticola (
n = 1), 16.7% for
Serratia marcesens (
n = 2), 16.7% for
Klebsiella pneumoniae (
n = 2), and 50% (
n = 6) for
Enterobacter cloacae. The endpoint PCR results showed 11 colonies positive for
blaBIL (91.7%), 11 for
blaSHV (91.7%), 11 for
blaCTX (97.7%), 12 for
blaDHA (100%), four for
blaVIM (33.3%), two for
blaOXA (16.7%), two for
blaIMP (16.7%), one for
blaKPC (8.3%), and one for
blaTEM (8.3%) gen; all samples were negative for
blaROB,
blaCMY,
blaP,
blaCFX and
blaLAP gene. The sequencing analysis revealed a specific genotype for
Enterobacter cloacae (blaSHV-12, blaCTX-M-15, blaDHA-1, blaKPC-2);
Serratia marcescens (blaSHV-1, blaCTX-M-3, blaDHA-1, blaVIM-2);
Klebsiella pneumoniae (blaSHV-12, blaCTX-M-15, blaDHA-1);
Serratia fonticola (blaSHV-12, blaVIM-1, blaDHA-1); and,
Enterobacter aerogene (blaSHV-1, blaCTX-M-1, blaDHA-1, blaVIM-2, blaOXA-9). Our results indicate that beta-lactam-resistant bacteria have acquired integrons with a different number of genes that provide pan-resistance to beta-lactam antibiotics, including penicillins, oxacillins, cefalosporins, monobactams, carbapenems, and imipenems.
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