ANTIBIOTIC RESISTANCE IN ENTEROPATHOGENIC ESCHERICHIA COLI AND CAMPYLOBACTER SPP. FROM BEEF AND RAW COW MILK
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Date
2023-03-23
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY
Abstract
The present study was conducted to detect the presence of antibiotic resistance in enteropathogenic Escherichia coli and Campylobacter spp. isolated from beef and raw cow milk. A total of 200 beef and 200 raw cow milk samples
were collected from various retail outlets and milk societies of Thrissur and Ernakulam districts. The samples were initially subjected to conventional culture techniques followed by biochemical tests. Escherichia coli and Campylobacter spp.
was detected in 49.5 and 1.5 per cent of the total samples, respectively. There was significant difference (p<0.01) between the occurrences of E. coli in milk samples of Thrissur and Ernakulam districts. On molecular confirmation, using PCR, 139 E. coli isolates were confirmed as enteropathogenic and out of six Campylobacterisolates obtained, five isolates generated amplicons for mapA and one for ceuE genes, representing C. jejuni and C. coli, respectively. The confirmed isolates were subjected to antibiotic sensitivity testing against fifteen commonly used antibiotics. Except doxycycline and cefotaxime, all the 139 EPEC isolates were resistant tothirteen antibiotics used in the study. High level of resistance was observed against ampicillin (67.62 per cent) and lowest to doxycycline (4.31 per cent). Multiple antibiotic resistance (MAR) index of the each isolates were calculated and the MAR index for EPEC ranged from 0 to 0.60. In Campylobacter spp. high level of resistance was observed against cefotaxime (83.33 per cent) and high susceptibilitywas detected in amoxiclav, co-trimoxazole, tetracycline and trimethoprim (16.66 per cent). The MAR index of Campylobacter spp. ranged from 0 to 0.27. A total of 63 trimethoprim, 65 sulphamethoxazole and 44 streptomycin resistant isolates were obtained from enteropathogenic E. coli and two trimethoprim, one sulphamethoxazole resistant isolates from Campylobacter spp. by disc diffusion method. The isolates which showed phenotypic resistance to trimethoprim were subjected to PCR for the detection of dfrA1 and dfrA10 genes. Similarly isolates that showed resistance to streptomycin were screened for presence of aadA1 and aadA2 genes and sulphamethoxazole resistant isolates were screened for sul1 and sul2 genes. Among the phenotypically resistant isolates of trimethoprim, 57.14 per cent were positive for dfrA1 and only 6.35 per cent were positive for dfrA10 genes. Similarly, in case of co-trimoxazole resistance genes sul1 and sul2 were detected in 32.30 and 55.38 per cent of isolates, respectively. One isolate each ofCampylobacter jejuni were positive for sul2 and dfrA1 genes. Streptomycin resistance gene aadA1 and aadA2 was detected in 34.09 and 52.27 per cent of EPEC isolates, respectively. The presence of multidrug efflux pump gene cmeB was detected in the Campylobacter spp. The representative amplicons of the resistance genes were sequenced and submitted to National Center for Biotechnology Information (NCBI), and accession numbers were obtained. The results of the study revealed that beef and milk acts as an important reservoir of antibiotic resistant E. coli and Campylobacter spp. In order to effectively control the emergence and spread of resistant infections, specific control strategies which acknowledge antibiotics stewardship in food producing animals should be implemented.