The Effect of Culture-Medium on Becteriocin Production in Some Bacterial Strains

Veterinarni Medicina 37, 1992, 661-666

Some staphylococcus and enterocoocus strains were used to investigate the effect of culture medium on bacteriocin production. Staphylococcus cohnii SC7, Staphylococcus sp. ZTJ 151, S. saprophyticus SS 877, Enterococcus faecium EF1 and E. faecalis EFG2 were isolated from the rumen wall and contents of lambs, calves and fallow deer, Enterococcus gallinarum EG10 and E. avium EA12 were isolated from the caecum of Japanese quail. The tested bacteria belong to producers with a wide antimicrobial effectiveness spectrum, they have low to medium adherence and urease activity (Tab. III. These culture media were used to test the effect of culture medium on bacteriocin production: nutrient agar no. 2 and VL agar enriched with 2 % of glucose and lactose (ZAG, ZAL, VLG, VLL), agar for isolation of faecal streptococci (SA) and the base for blood agar no. 4 and no. 2 (KA4, KA2). The strains Streptococcus bovis AO 24/85 and Staphylococcus aureus Oxford 209 P were used as indicator bacteria. Tables I and II show the results of these tests. The tested strains produced the widest inhibition zones (6 mm) with both indicators on SA medium, and this indicates massive bacteriocin production. On ZAG medium, the zones of enterococci with the AO 24/85 strain were larger size than those of staphylococci, but the zones were dim. All strains with the 209 P indicator produced dim zones of the 2mm size. The larger inhibition zones (2-5 mm) in comparison with staphylococci were observed in enterococci on the ZAL medium with the AO 24/85 strain. The production of tested strains was balanced on VLG agar with respect to the use of both indicators. The bacteria produced dim zones of small size on VLL and KA4 media. There were large differences in production between the different strains on KA2 medium. These results document that bacteriocin production depends not only on the indicator organism, but also on a convenient culture medium

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