Antimicrobial activity of the isolates was determined by the agar
spot procedure described by Biswas, Ray, Johnson, and Ray (1991).
For the agar spot test, overnight cultures of the S. epidermidis strains
were spotted (5 mL) onto the surface of Tryptic SoyAgar (TSA, Merck®,
USA) plates and incubated for 24 h at 37 C to allowcolony formation.
The plateswere then overlaid with 8mL soft-TSA containing 50 mL of
the active culture of the test strain and examined after 24 h for inhibition
zone. In this experiment, Listeria monocytogenes 7644, S.
aureus ATCC 25923, Salmonella enterica Typhimurium SL1344 ve
Escherichia coli CFA 1 were used as test microorganisms.