Predominance of Multidrug Resistant Zoonotic Salmonella Enteritidis Genotypes in Poultry of Bangladesh

Salmonella infection is one of the major constraints in poultry farming that has hindered its development in Bangladesh. Salmonella serotypes with multidrug resistant phenotypes are a threat to the poultry of Bangladesh. This study focused on genotypic characterization of Salmonella spp. isolated previously from 5 different poultry farms of Savar, Bangladesh. Among the 67 Salmonella isolates, 12 were found to be plasmid-free and showed resistance to as high as 7 groups of antibiotics. PCR using Salmonella specific primers ascertained that all 67 isolates were invA gene positive, 17 were sefA gene positive and 4 were fliC gene positive. Genotyping using Random Amplified Polymorphic DNA (RAPD) and Amplified Ribosomal DNA Restriction Analysis (ARDRA) differentiated three distinct genetic variants circulating in five poultry farms indicating no single source of infection. Sequencing of representatives from each genotype detected close similarity to S. Enteritidis, S. Typhimurium and S. Heidelberg within the poultry samples indicating significant zoonotic hazard. S. Enteritidis was highly prevalent, accounting for 88% (59 out of 67) of the poultry isolates. Contaminations or prevalence of such multidrug resistant zoonotic Salmonella indicates an unhygienic practice of poultry farming in Bangladesh which is becoming a potential threat to public health.