Isolation and Characterization of Salmonella Enterica Serovar Typhimurium Circulating Among Healthy Chickens of Bangladesh

Salmonella is considered as a global problem ranking first among food borne diseases. All motile Salmonella of poultry origin are zoonotic and readily transmit to human via meat and eggs but reports on non - typhoidal Salmonella serovars circulating in layer chickens is very limited in South-East Asian countries including Bangladesh. Salmonella serovars isolated from apparently healthy chickens were characterized in the present study. Of 170 samples (cloacal swab 150 and feed 20) collected from commercial layer farms, motile Salmonella was isolated 4% (6/150) and 50% (10/20) respectively by cultural, biochemical, motility test and by detection of hisJ gene. About 5% (8/170) samples possessed serovar-specific gene fimA, suggesting that isolates were Salmonella enterica serovar Typhimurium. Antimicrobial susceptibility testing demonstrated that the isolated serovars were multidrug resistant. Therefore apparently healthy layer chickens harbour and transmit S. Typhimurium to the environment, although little is alarming since it has zoonotic significance and the isolates were resistant to commonly used first line of antibiotic in Salmonella infection.