Occurrence, Risk Factors, Serotypes and Antimicrobial Resistance of Salmonella Strains Isolated from Imported Fertile Hatching Eggs, Hatcheries, and Broiler Farms in Trinidad and Tobago.

This cross-sectional study determined the occurrence, risk factors and characteristics of Salmonella isolated from imported broiler hatching fertile eggs, hatcheries, and broiler farms in Trinidad and Tobago. Standard methods were used to isolate and characterize Salmonella isolates from two broiler hatcheries and 27 broiler farms in the country. Salmonella was isolated from 0.0% (0/45), 7.6% (12/158) and 2.8% (24/866) of fertile hatching eggs (composite of 450), hatcheries and broiler farms, respectively (p=0.006). The highest frequency of Salmonella isolation was detected in stillborn chicks, 28.0% (7/28) and in cloacal swabs, 2.2% (15/675) in samples collected from the hatcheries and farms, respectively. None of the 15 farm management and production practices investigated was significantly (P>0.05) associated with the isolation of Salmonella . The predominant serotypes among Salmonella were Kentucky (83.3%) and Infantis (62.5%) for hatchery and farms isolates, respectively. The disc diffusion method revealed a frequency of antimicrobial-resistant Salmonella of 44.0% (11/25) and 87.5% (35/40) in isolates from the hatcheries and broiler farms, respectively (p=0.0002). Antimicrobial resistance was highest (28.0%) to doxycycline and kanamycin for hatchery isolates, while for farm isolates resistance was high (>65%) to sulphamethoxazole-trimethoprim, gentamycin, ceftriaxone, kanamycin, and doxycycline. Multi-drug resistance (MDR) was exhibited by 4.0% and 85.7% of Salmonella isolates from the hatcheries and farms, respectively (p<0.0001). The high antimicrobial resistance and MDR exhibited by Salmonella from broiler farms highlight the therapeutic implications and the potential to enter the food chain.