Studies on detection and antibiotic sensitivity and resistance pattern of Listeria monocytogenes isolated from cattle, raw cow milk and milk products from Tripura, India

Abstract

A total 200 numbers of samples including cattle faeces (50), raw milk (50) and milk products (100) were collected randomly to study the occurrence and antibiotic sensitivity of L. monocytogenes from West Tripura district, Tripura. The L. monocytogenes was isolated by using two step enrichment method of culturing and identified based on cultural characteristics, gram staining, biochemical properties, tumbling motility and in vitro pathogenicity tests. The antibiotic sensitivity was studied against 12 numbers of commonly used antibiotics in animals and human. The occurrence of L. monocytogenes was recorded as 8.50 percent including 6.00 percent (3/50) from cattle faeces, 8.00 percent (4/50) from raw milk, 12.00 percent (3/25) from lassi, 16.00 percent (4/25) from dahi and 12.00 percent (3/25) in ice-cream. The L. monocytogenes strains showed 100 percent sensitivity towards Penicillin, Ampicillin, Oxacillin, Cephotaxime /Clavulanic acid, Ciprofloxacin, Tetracycline and Trimethoprim/Sulphamethoxazole followed by Streptomycin (88.23%), Chloramphenicol (82.35%), Gentamicin (70.58%) and Ceftriaxone (52.94%). The presence of the organism in milk and milk products indicates unhygienic handling during production, processing and marketing is an alarming public health threat to the consumers.