Dr. Binsy MathewRADHIKA A. N.2024-03-182024-03-182022-02-10https://krishikosh.egranth.ac.in/handle/1/5810207537The present study was undertaken to detect colistin and quinolone resistant Salmonella enterica from poultry processing lines. A total of 450 samples were collected which included 75 samples each of cloacal swabs, caecal contents and carcass rinsates from two processing plants viz., Plant A, Thrissur and Plant B, Ernakulam. The samples were subjected to isolation of Salmonella by conventional culture technique and Salmonella were detected in 14.22 per cent of the samples. There was significant difference (p < 0.05) in the occurrence of Salmonella spp. in cloacal swabs and carcass rinsates of two processing plants. The molecular confirmation of positive isolates targeting invA gene for Salmonella genus and iroB gene for Salmonella enterica species was detected in 67.19and81.4per cent of isolates, respectively. The Salmonella enterica confirmed isolates were subjected to antibiotic sensitivity against quinolones by disc diffusion method and colistin agar test for colistin; wherein, highest resistance was observed to enrofloxacin and levofloxacin, whereas 8.57 per cent of the isolates were resistant to colistin. For molecular confirmation of quinolone resistance mismatch amplification mutation assay (MAMA) PCR was employed to detect mutations in gyrA and parC genes, 15.15 per cent of isolates had mutations in gyrA gene but none of the isolates had mutations in parC gene. The qnrS gene was present in 18.18 per cent of the isolates. However, none of the isolates harboured oqxAB gene. For molecular confirmation of colistin resistance,mutations in pmrA and pmrB genes were analysed by sequencing; out of three resistant isolates, two isolates viz., pmrA1 and pmrA2 had mutations in pmrA gene at 345th and 346th position, respectively. Further, two pmrB harbouring isolates showed mutation in 79th, 244th, 319th, 388th and 577th position of the sequence. All the representative amplicons of the genes were sequenced and submitted to the NCBI. The results of the study revealed the occurrence of antibiotic resistant Salmonella enterica throughout the poultry or chickenprocessing lines. In order to prevent antibiotic resistant Salmonella contamination in the processing line elucidating risk factors is necessary and implementation of one health approach in the meat production so as to ensure food safety to the consumers.EnglishThesis