Salmonella from Farm to Table: Isolation, Characterization, and Antimicrobial Resistance of Salmonella from Commercial Broiler Supply Chain and Its Environment.

M Nasim Sohail,B M Veeregowda,H D Naryanaswamy,S Chandra Priya,S Isloor,D Rathnamma,S Wilfred Ruban,Stefania Cantore

doi:10.1155/2021/3987111

M Nasim Sohail, B M Veeregowda + Show 6 more

Open Access

https://doi.org/10.1155/2021/3987111

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Abstract

Antimicrobial resistance (AMR) in poultry production chain is one of the major food safety concerns due to indiscriminate usage of antibiotics and the presence of pathogens such as Salmonella which causes infections in various stages of production. In the present study, 182 samples were collected from commercial broiler supply chain, viz., three hatcheries (n = 29), three commercial broiler farms (CBF; n = 99), and three retail meat shops (RMS; n = 54), and used for isolation and identification of Salmonella using three different selective agar media and a selective enrichment medium followed by PCR confirmation targeting the hilA gene. The overall prevalence of Salmonella was 47/182 (25.82%), and a significantly higher (P < 0.05) prevalence was observed in retail meat shops (46.29%), CBF (19.19%), and hatcheries (10.34%). Comparison of three agar media for isolation of Salmonella revealed that all the media were equally selective. However, PCR amplification of hilA gene fragment was significantly higher (P < 0.01) in selective enrichment culture tetrathionate brilliant green bile broth (TTB) as compared to all solid (agar-based) media. Susceptibility pattern against most frequently used antibiotics revealed that 100% of the isolates were resistant to at least one antibiotic. High resistance was observed for doxycycline (94.34%), followed by cefpodoxime (84.91%), ciprofloxacin (72.64%), gentamicin (65.09%), enrofloxacin (61.32%), colistin sulphate (40.42%), amikacin (34.91%), ampicillin (33.96%), neomycin (33.02), cefotaxime (30.19%), ceftazidime (29.25%), trimethoprim-sulfamethoxazole (23.58%), amoxicillin+clavulanic acid (21.70%), and chloramphenicol (12.26%); 16.98% of the isolates were ex-tended spectrum β-lactamase (ESBL) producers, and 76.41% were multidrug resistant (MDR). MDR Salmonella were significantly higher (P < 0.01) in RMS (91.66%) followed by CBF (82.75%), whereas no MDR isolates were present in the isolates from hatcheries. The results indicated a higher prevalence of Salmonella and AMR for commonly used antibiotics in the complete broiler supply chain, especially RMS and CBF. Also, this study idicated that TTB enrichment followed by PCR and colony PCR was found to be rapid, specific and time-saving method.

Highlights

Worldwide, broiler production is an intensive system which comprises of several entities, including the breeding sector, the hatcheries, and the production sector
All the 182 samples collected from hatcheries, commercial broiler farms (CBF), and retail meat shops (RMS) after selective enrichment were plated onto three different selective media Xylose Lysine Deoxycholate (XLD), Xylose Lysine Tergitol 4 (XLT4), and Brilliant Green Agar with Phosphates (BGA), and samples that revealed black centred colonies with red coloration of the media on XLD and XLT4 and pink or pinkish white colonies on BGA were considered to be presumptive for Salmonella
Colonies that appeared irregularly shaped, translucent, and black centred with red coloration of the media in XLD and XLT4 were confirmed to be Salmonella by both biochemical tests and PCR (Figures 2 and 3), whereas colonies that appeared regular, opaque, and black centred without red coloration in XLD and XLT4 (Figures 4 and 5) were negative for Salmonella by both biochemical tests and PCR

Summary

Introduction

Broiler production is an intensive system which comprises of several entities, including the breeding sector, the hatcheries, and the production sector. Any of these stages of production could serve as the source for pathogenic microorganisms. In addition to causing foodborne illness, Salmonella from broiler production chain have been found to be resistant to antibiotics [5] [6], and this is a growing concern requiring attention for mitigating antimicrobial resistance (AMR). Even though it has been documented that poultry and its products are the major source of Salmonella causing illness in humans, their role in the transmission of AMR pathogens and antibiotic resistance genes (ARGs) into the food chain is only gaining prominence

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