Molecular Characterization of Salmonella Detected along the Broiler Production Chain in Trinidad and Tobago.

Anisa Sarah Khan,Meghan Maguire,Cong Li,Woubit Abebe,Karla Georges,Rian Ewald Pierneef,Abiodun Adewale Adesiyun,Sherry Ayers,Gregory H Tyson,Narjol Gonzalez-Escalona

doi:10.3390/microorganisms10030570

Abstract

This cross-sectional study determined the serovars, antimicrobial resistance genes, and virulence factors of Salmonella isolated from hatcheries, broiler farms, processing plants, and retail outlets in Trinidad and Tobago. Salmonella in silico serotyping detected 23 different serovars where Kentucky 20.5% (30/146), Javiana 19.2% (28/146), Infantis 13.7% (20/146), and Albany 8.9% (13/146) were the predominant serovars. There was a 76.0% (111/146) agreement between serotyping results using traditional conventional methods and whole-genome sequencing (WGS) in in silico analysis. In silico identification of antimicrobial resistance genes conferring resistance to aminoglycosides, cephalosporins, peptides, sulfonamides, and antiseptics were detected. Multidrug resistance (MDR) was detected in 6.8% (10/146) of the isolates of which 100% originated from broiler farms. Overall, virulence factors associated with secretion systems and fimbrial adherence determinants accounted for 69.3% (3091/4463), and 29.2% (1302/4463) counts, respectively. Ten of 20 isolates of serovar Infantis (50.0%) showed MDR and contained the blaCTX-M-65 gene. This is the first molecular characterization of Salmonella isolates detected along the entire broiler production continuum in the Caribbean region using WGS. The availability of these genomes will help future source tracking during epidemiological investigations associated with Salmonella foodborne outbreaks in the region and worldwide.

Highlights

Isolates of Salmonella recovered from the four combinations of media (RVS/brilliant green agar (BGA), Rappaport-Vassiliadis Soya (RVS)/xylose lysine tergitol 4 (XLT-4), TT/BGA, and TT/XLT-4) were initially screened using the conventional slide agglutination test
Five additional human clinical isolates of Salmonella obtained from the Caribbean Public Health Agency (CARPHA)
This study highlighted the antimicrobial resistance and virulence genes associated with Salmonella serovars isolated along the broiler production chain in Trinidad and Tobago

Summary

Introduction

Since the 1950s, Salmonella has been highlighted as an economically important zoonotic pathogen by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) [1]. The ability of Salmonella to cause self-limiting gastroenteritis, coupled with high mortality rates in humans due to invasive infections are causes for public health concerns [2,3]. While many animals serve as reservoirs for Salmonella, poultry, and poultry products are one of the primary sources of salmonellosis in humans. The possibility of transmission from reservoirs to other animals and Microorganisms 2022, 10, 570.

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