Detection of Antimicrobial Resistance by Phenotypic and Genotypic Methods in E. coli Isolated from Diarrhea of Cattle Calves in Mhow, Indore

Background: Neonatal calf diarrhoea, a complex illness, continues to be the leading cause of neonatal calf deaths. The complex pathophysiology of infectious calf diarrhoea results in severe losses to the dairy sector, either directly via mortality or indirectly through the costs of prophylaxis and slowed growth in infected calves. Neonatal calf diarrhoea during the first month of life causes between 80 to 85 per cent of all deaths in India. Methods: A total 137 cattle calve diarrhea samples were collected from calves that show clinical signs of diarrhea. Swabs of the rectum were taken directly from diarrhoeic calves and collected in sterile test tubes. They were then immediately transported to the laboratory for the isolation of E. coli. Result: A total 64 E. coli isolates were detected and identified from samples via biochemical and molecular assays employing PCR targeting the E. coli specific 16s rRNA gene. The result of antibiotic sensitivity of 64 isolated strains of E. coli to 15 antimicrobial drugs shows highest sensitivity towards antibiotic gentamycin (68.75%) followed by sulfadiazine and co-trimoxazole (39.06), ciprofloxacin (32.81%) and highest resistance against ampicillin (87.5%) followed by ceftriaxone (82.813%), ceftazidime plus clav (81.25%). There is the variation in the expression of the AMR genes in the isolated E. coli strains. The detection rate of AMR gene blaTEM was highest 90% and that of aadA was the lowest (0%). The other AMR genes blaCTX-M, blaSHV, sul1 and tetA showing 50%, 20%, 50% and 30%.