Division of Veterinary Public Health, Indian Veterinary Research Institute, Izatnagar -243 122 (U.P.)
Influence of various selective agents viz. acriflavine, nalidixic acid, bacitracin and ceftazidime was evaluated on the growth of stressed and non-stressed Listeria spp. and other non-listerial isolates. Different isolates of L. monocytogenes, other Listeria spp., Bacillus cereus, E. coli, Enterococcus fecalis and Staphylococcus aureus were inoculated on brain heart infusion agar containing 0.5% yeast extract and various concentrations of selective agents. Growth pattern in six concentrations of acriflavine (5, 10, 15, 20, 25 and 50 mg/lit), four concentrations of bacitracin (2000, 4000, 8000, 16000 IU/lit), nalidixic supplementation at 10, 20, 40 and 80 mg/lit and five concentrations of ceftazidime (10, 20, 30, 40 and 50 mg/lit) were tested. It was observed that acriflavine, nalidixic acid, bacitracin and ceftazidime can be supplemented in the medium upto the concentrations of 20 mg, 20 mg, 4000 IU and 30 mg, respectively, for selective growth of stressed as well as non stressed Listeria spp.
