Virulence and antimicrobial resistance profile of non-typhoidal Salmonella enterica serovars recovered from poultry processing environments at wet markets in Dhaka, Bangladesh.

Nure Alam Siddiky,Tanvir Rahman,Mohammed A Samad,Abdul Kafi,Shahidur Rahman Khan,Samun Sarker,Kumar Venkitanarayanan

doi:10.1371/journal.pone.0254465

Nure Alam Siddiky, Tanvir Rahman + Show 5 more

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https://doi.org/10.1371/journal.pone.0254465

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Abstract

The rapid emergence of virulent and multidrug-resistant (MDR) non-typhoidal Salmonella (NTS) enterica serovars is a growing public health concern globally. The present study focused on the assessment of the pathogenicity and antimicrobial resistance (AMR) profiling of NTS enterica serovars isolated from the chicken processing environments at wet markets in Dhaka, Bangladesh. A total of 870 samples consisting of carcass dressing water (CDW), chopping board swabs (CBS), and knife swabs (KS) were collected from 29 wet markets. The prevalence of Salmonella was found to be 20% in CDW, 19.31% in CBS, and 17.58% in KS, respectively. Meanwhile, the MDR Salmonella was found to be 72.41%, 73.21%, and 68.62% in CDW, CBS, and KS, respectively. All isolates were screened by polymerase chain reaction (PCR) for eight virulence genes, namely invA, agfA, IpfA, hilA, sivH, sefA, sopE, and spvC. The S. Enteritidis and untyped Salmonella isolates harbored all virulence genes while S. Typhimurium isolates carried six virulence genes, except sefA and spvC. Phenotypic resistance revealed decreased susceptibility to ciprofloxacin, streptomycin, ampicillin, tetracycline, gentamicin, sulfamethoxazole-trimethoprim, amoxicillin-clavulanic acid, and azithromycin. Genotypic resistance showed a higher prevalence of plasmid-mediated blaTEM followed by tetA, sul1, sul2, sul3, and strA/B genes. The phenotypic and genotypic resistance profiles of the isolates showed a harmonic and symmetrical trend. According to the findings, MDR and virulent NTS enterica serovars predominate in wet market conditions and can easily enter the human food chain. The chi-square analysis showed significantly higher associations among the phenotypic resistance, genotypic resistance and virulence genes in CDW, CBS, and KS respectively (p < 0.05).

Highlights

Salmonella has been recognized as one of the common pathogens that cause gastroenteritis [1, 2] with significant morbidity, mortality, and economic loss [3, 4]
Based on the importance of foodborne Salmonella at wet markets, this study aimed at determining the pathogenicity and profile of antimicrobial susceptibility of Salmonella enterica serovars isolated from poultry processing environments in the wet markets of Dhaka, Bangladesh
Chicken carcasses are dressed and processed in the open environment of the wet market, which exacerbated the spread of pathogens

Summary

Introduction

Salmonella has been recognized as one of the common pathogens that cause gastroenteritis [1, 2] with significant morbidity, mortality, and economic loss [3, 4]. NTS serovars like Typhimurium and Enteritidis are the predominant worldwide among the 2,600 serotypes of Salmonella that have been identified [7, 8]. Salmonella grows in animal farms may contaminate eggs and/or meat during the slaughtering process before being transferred to humans through the food chain. Numerous previous studies have been reported the isolation of Salmonella from foods of animal origin as well as human samples [14,15,16,17]. Enteritidis are generally linked with the consumption of contaminated eggs and poultry meat, while S. Salmonella Typhimurium and Enteritidis are the most frequently reported serovars associated with human foodborne illnesses [22]. Untyped Salmonella of animal origin has been increasingly observed in Bangladesh [23, 24] but limited information has been published on Salmonella enterica serovars isolated from chicken processing environments

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