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.
