Occurrence of Multidrug Resistant Salmonella spp. in Poultry and Approach for Its Indigenous Bio-control

A significant limitation to flourish poultry industry in Bangladesh is the emergence of multidrug resistance pathogenic bacteria like Salmonella spp. due to uncontrolled use of antibiotics for disease treatment. An alternative to antibiotics could be the application of probiotics. About 120 cloacal-swabs from poultry birds were investigated, seventy two (72) isolates of Salmonella spp. and twenty two (22) isolates of lactic acid bacteria (out of 50)were identified respectively by cultural, morphological and biochemical tests presumptively. Antibiotic sensitivity test of Salmonella spp. was performed, followed by Kirby-Bauer disc-diffusion assay with six antibiotic groups. All those isolates of Salmonella spp. were found to be highly resistant to a-lactam, cephalosporin, tetracycline and macrolide, highly sensitive to carbapenem and moderately sensitive to aminoglycosides. Then Salmonella spp. were used as a target for the prospective probiotic bacteria which were screened based on antimicrobial activity against those multidrug resistance Salmonella spp. In antagonism assay such as disc diffusion and one-streak method, it was revealed that five lactic acid bacteria showed antimicrobial activity against Salmonella spp. Further, lactic acid bacteria were characterized based on their tolerance ability to pH and NaCl, antibiotic susceptibility test. The tolerance range of Lactic acid bacteria was about pH (3.5-9.5), NaCl (4-8) % and also resistant to antibiotics groups like B lactam, aminoglycosides, and quinolone. Then 16S rDNA gene sequence analysis was performed for molecular identification of potential probiotic bacteria. One representative isolate was identified as phylogenetically closed relative to Pediococcus acidilactici. This study was able to demonstrate that Pediococcus acidilactici as anindigenous probiotic candidate to inhibit the growth of isolated multidrug resistant Salmonella spp. in poultry. The potent probiotic candidate Pediococcus sp. could be used to counter bacterial diseases in poultry, thereby it could ensure food safety in the poultry industries of Bangladesh. Bangladesh J Microbiol, Volume 34 Number 2 December 2017, pp 83-90