Detection of ESBL and ACBL-producing Salmonella enterica in Cattle from Different Districts of South Bengal

Background: Salmonella spp. is a pathogenic bacterium that can cause infection in animals and human beings. Drug-resistant Salmonellae make this infection more deadly. In this background, this study was undertaken to investigate the prevalence and antimicrobial resistance pattern of ESBL / ACBL-producing Salmonella enterica strains, obtained from bovine faecal samples from different districts of West Bengal. Methods: A total of 170 bovine faecal samples were aseptically collected from Purba Barddhaman, Birbhum and North 24 Paraganas in this study. Standard procedures were followed to identify Salmonella enterica isolates followed by their detailed characterization and in-vitro antibiogram. Result: A total of 35 (20.59%) Salmonella spp. isolates were recovered after detailed morphological and biochemical characterization which were also confirmed by PCR. Higher prevalence was recorded in cross-breed jerseys (88.57%) and younger cattle within 2 yrs. of age (24.53%). A total of 18 Salmonella spp. (51.24%) isolates were detected as ESBL and 29 Salmonella spp. (82.86%) isolates were detected as ACBL producers both phenotypically. In molecular characterization, the blaAmpC (91.43%) gene was the highest followed by other genes. No TEM gene was detected in this study. Antibiogram of all the ESBL-producing Salmonella spp., isolates showed high-level resistance (58-92%) to various antibiotics like cefotaxime, doxycycline, ampicillin/cloxacillin, tetracycline, enrofloxacin etc. Antibiotics like azithromycin, chloramphenicol, HL gentamicin etc. were sensitive to these isolates.