Isolation, Identification and Antibiotic Susceptibility Profiling of Antimicrobial Resistant Listeria monocytogenes from Dairy Farm

Abstract

The objective of the present study was to evaluate the antibiotic susceptibility of 25 Listeria monocytogenes isolates isolated from raw cattle milk towards 15 antibiotics presently used in veterinary and human therapy. Antibiotic susceptibility tests were performed by using the Kirby Bauer disk diffusion method. The isolates were tested for their susceptibility to 15 different common antimicrobial drugs. A total of 115 milk samples from various sources were cultured for incidence of L. monocytogenes. 25 isolates of L. monocytogenes were isolated from a total of the 115 samples. Several isolates from milk samples were found resistant to Nalidixic acid, Amoxycillin+sulbactum, Cloxacillin, Erythromycin, Kanamycin and Vancomycin. On the other hand, several isolates were found susceptible to the Ofloxacin, Ampicillin, Tetracycline, Oxacillin, Streptomycin, Sulphafurazole and Ciprofloxacin. The present study provides preliminary information on incidence of L. monocytogenes as milk contaminants which may act as vehicles for the transmission of drug resistance.