Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>

<i>Salmonella enteritidis</i> is a major cause of foodborne illness worldwide, and the emergence of ciprofloxacin-resistant strains poses a significant threat to food safety and public health. This study aimed to investigate the prevalence, spread, and mechanisms of ciprofloxacin resista...

Full description

Saved in:
Bibliographic Details
Main Authors: Zengfeng Zhang, Hang Zhao, Chunlei Shi
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Foods
Subjects:
Online Access:https://www.mdpi.com/2304-8158/14/2/289
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832588421624758272
author Zengfeng Zhang
Hang Zhao
Chunlei Shi
author_facet Zengfeng Zhang
Hang Zhao
Chunlei Shi
author_sort Zengfeng Zhang
collection DOAJ
description <i>Salmonella enteritidis</i> is a major cause of foodborne illness worldwide, and the emergence of ciprofloxacin-resistant strains poses a significant threat to food safety and public health. This study aimed to investigate the prevalence, spread, and mechanisms of ciprofloxacin resistance in <i>S. enteritidis</i> isolates from food and patient samples in Shanghai, China. A total of 1625 <i>S. enteritidis</i> isolates were screened, and 34 (2.1%) exhibited resistance to ciprofloxacin. Pulsed-field gel electrophoresis (PFGE) results suggested that clonal spread might have persisted among these 34 isolates in the local area for several years. Multiple plasmid-mediated quinolone resistance (PMQR) genes, GyrA mutations in the quinolone resistance-determining region (QRDR), and overexpression of RND efflux pumps were identified as potential contributors to ciprofloxacin resistance. PMQR genes <i>oqx</i>AB, <i>qnr</i>A, <i>qnr</i>B, and <i>aac</i>(6’)-Ib-cr as well as GyrA mutations S83Y, S83R, D87Y, D87G, D87N, and S83Y-D87Y were identified. The co-transfer of the PMQR gene <i>oqx</i>AB with the ESBL gene <i>bla</i><sub>CTX-M-14/55</sub> on an IncHI2 plasmid with a size of ~245 kbp was observed through conjugation, highlighting the role of horizontal gene transfer in the dissemination of antibiotic resistance. Sequencing of the <i>oqx</i>AB-bearing plasmid p12519A revealed a 248,746 bp sequence with a typical IncHI2 backbone. A 53,104 bp multidrug resistance region (MRR) was identified, containing two key antibiotic resistance determinants: IS<i>26</i>-<i>oqx</i>R-<i>oqx</i>AB-IS<i>26</i> and IS<i>26</i>-ΔIS<i>Ecp1</i>-<i>bla</i><sub>CTX-M-14</sub>-IS<i>903B</i>. The findings of this study indicate that ciprofloxacin-resistant <i>S. Enteritidis</i> poses a significant threat to food safety and public health. The persistence of clonal spread and the horizontal transfer of resistance genes highlight the need for enhanced surveillance and control measures to prevent the further spread of antibiotic resistance.
format Article
id doaj-art-7abaf59a8fd140af9cde555dd20e9608
institution Kabale University
issn 2304-8158
language English
publishDate 2025-01-01
publisher MDPI AG
record_format Article
series Foods
spelling doaj-art-7abaf59a8fd140af9cde555dd20e96082025-01-24T13:33:09ZengMDPI AGFoods2304-81582025-01-0114228910.3390/foods14020289Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>Zengfeng Zhang0Hang Zhao1Chunlei Shi2MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, ChinaMOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, ChinaMOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China<i>Salmonella enteritidis</i> is a major cause of foodborne illness worldwide, and the emergence of ciprofloxacin-resistant strains poses a significant threat to food safety and public health. This study aimed to investigate the prevalence, spread, and mechanisms of ciprofloxacin resistance in <i>S. enteritidis</i> isolates from food and patient samples in Shanghai, China. A total of 1625 <i>S. enteritidis</i> isolates were screened, and 34 (2.1%) exhibited resistance to ciprofloxacin. Pulsed-field gel electrophoresis (PFGE) results suggested that clonal spread might have persisted among these 34 isolates in the local area for several years. Multiple plasmid-mediated quinolone resistance (PMQR) genes, GyrA mutations in the quinolone resistance-determining region (QRDR), and overexpression of RND efflux pumps were identified as potential contributors to ciprofloxacin resistance. PMQR genes <i>oqx</i>AB, <i>qnr</i>A, <i>qnr</i>B, and <i>aac</i>(6’)-Ib-cr as well as GyrA mutations S83Y, S83R, D87Y, D87G, D87N, and S83Y-D87Y were identified. The co-transfer of the PMQR gene <i>oqx</i>AB with the ESBL gene <i>bla</i><sub>CTX-M-14/55</sub> on an IncHI2 plasmid with a size of ~245 kbp was observed through conjugation, highlighting the role of horizontal gene transfer in the dissemination of antibiotic resistance. Sequencing of the <i>oqx</i>AB-bearing plasmid p12519A revealed a 248,746 bp sequence with a typical IncHI2 backbone. A 53,104 bp multidrug resistance region (MRR) was identified, containing two key antibiotic resistance determinants: IS<i>26</i>-<i>oqx</i>R-<i>oqx</i>AB-IS<i>26</i> and IS<i>26</i>-ΔIS<i>Ecp1</i>-<i>bla</i><sub>CTX-M-14</sub>-IS<i>903B</i>. The findings of this study indicate that ciprofloxacin-resistant <i>S. Enteritidis</i> poses a significant threat to food safety and public health. The persistence of clonal spread and the horizontal transfer of resistance genes highlight the need for enhanced surveillance and control measures to prevent the further spread of antibiotic resistance.https://www.mdpi.com/2304-8158/14/2/289<i>Salmonella enteritidis</i>ciprofloxacin resistancePMQR<i>gyr</i>Aefflux pump
spellingShingle Zengfeng Zhang
Hang Zhao
Chunlei Shi
Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
Foods
<i>Salmonella enteritidis</i>
ciprofloxacin resistance
PMQR
<i>gyr</i>A
efflux pump
title Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
title_full Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
title_fullStr Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
title_full_unstemmed Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
title_short Clonal Spread and Genetic Mechanisms Underpinning Ciprofloxacin Resistance in <i>Salmonella enteritidis</i>
title_sort clonal spread and genetic mechanisms underpinning ciprofloxacin resistance in i salmonella enteritidis i
topic <i>Salmonella enteritidis</i>
ciprofloxacin resistance
PMQR
<i>gyr</i>A
efflux pump
url https://www.mdpi.com/2304-8158/14/2/289
work_keys_str_mv AT zengfengzhang clonalspreadandgeneticmechanismsunderpinningciprofloxacinresistanceinisalmonellaenteritidisi
AT hangzhao clonalspreadandgeneticmechanismsunderpinningciprofloxacinresistanceinisalmonellaenteritidisi
AT chunleishi clonalspreadandgeneticmechanismsunderpinningciprofloxacinresistanceinisalmonellaenteritidisi