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Occurrence of extended-spectrum β-lactamase, AmpC and virulence genes in Escherichia coli isolates from vegetable salads in Morocco

Kaotar Nayme (Molecular Bacteriology Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco)
Abouddihaj Barguigua (Département de Biologie-Géologie, Faculté polydisciplinaire, Université Sultan Moulay Slimane, Beni Mellal, Morocco)
Brahim Bouchrif (Food Microbiology Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco)
Idrissa Diawara (Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, Casablanca, Morocco)
Fatima El Otmani (Microbiology, Health and Environment Team Research, Department of Biology, Faculty of Sciences, Chouaib Doukkali University, El Jadida, Morocco)
Naima Elmdaghri (Molecular Bacteriology Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco)
Khalid Zerouali (Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, Casablanca, Morocco)
Mohammed Timinouni (Institut Pasteur du Maroc, Casablanca, Morocco)

British Food Journal

ISSN: 0007-070X

Article publication date: 3 July 2017

Abstract

Purpose

The purpose of this paper is to assess the occurrence of the extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamase genes in 144 Escherichia coli isolates recovered from 160 vegetable salad samples.

Design/methodology/approach

Among the 144 E. coli isolates recovered from 160 vegetable salads, 17 (12 percent) ceftazidime-resistant isolates were screened for ESBL production with the double disk-diffusion test. The ESBL-producing isolates were characterized for antimicrobial resistance, the presence of virulence genes and plasmid-mediated quinolone resistance (PMQR) determinants. The isolates were also subjected to phylogenetic group typing. The existence of plasmid AmpC genes and mutations in the regulatory region of the chromosomal AmpC gene was assessed using polymerase chain reaction (PCR) and sequencing. All β-lactamase isolates were further characterized by pulsed-field gel electrophoresis to determine the genetic relatedness.

Findings

Overall, 17 (12 percent) of the 144 E. coli isolates studied were ceftazidime resistant. Among the 17 isolates, 13 (77 percent) were multidrug resistant and four (23.5 percent) were ESBL producers. The bla CTX-M14 was the only gene detected. Of the 12 AmpC-producing isolates, three (18 percent) harbored plasmid-encoded AmpC and sequencing analysis of the chromosomal AmpC genes revealed mutations in the promoter/attenuator region. PMQR determinants were detected in 9 (52 percent) isolates. A was the most prevalent phylogenetic group (56 percent), followed by groups B1 (31 percent), D (6 percent), and B2 (6 percent). PCR showed that six (50 percent) ESBL/AmpC-producing E. coli isolates carried one and/or two virulence genes. Pulsed-field gel electrophoresis showed no epidemiological relationship between these isolates.

Originality/value

This study places vegetable salads within the spectrum of ecological niches that may be vehicles for antibiotic-resistant bacteria/genes with clinical interest and these findings are worthy of attention as their spread to humans by ingestion cannot be dismissed.

Keywords

Acknowledgements

Conflict of interest: there is no conflict of interest to declare.

Citation

Nayme, K., Barguigua, A., Bouchrif, B., Diawara, I., El Otmani, F., Elmdaghri, N., Zerouali, K. and Timinouni, M. (2017), "Occurrence of extended-spectrum β-lactamase, AmpC and virulence genes in Escherichia coli isolates from vegetable salads in Morocco", British Food Journal, Vol. 119 No. 7, pp. 1633-1647. https://doi.org/10.1108/BFJ-11-2016-0573

Publisher

:

Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited