PRODUCTION OF BACTERIOCIN-LIKE SUBSTANCES BY STRAINS OF ENTEROCOCCI, STREPTOCOCCI AND STAPHYLOCOCCI ISOLATED FROM JAPANESE-QUAIL

The production of bacteriocin-like substances was investigated in some strains of enterococci, streptococci and staphylococci which were isolated from the caecum of six Japanese quails. Japanese quails are a model specimen for cosmic research within the Intercosmos-Incubator Programme. The quails were divided into three groups. The first couple was put into an incubator on the spaceship board and the flight took seven days. The second couple was a synchronized control (cosmic flight conditions simulated on the Earth) and the third couple was a laboratory control. Diagnostic tests were used to select the strains belonging to the species Enterococcus avium (EA 7), Enterococcus gallinarum (EG 10, EG 12), Streptococcus sp. (Ss 2, Ss 11), Staphylococcus gallinarum (SG 1, SG 2) and Staphylococcus sp. (S 7). Thirteen indicator strains of different origin (Gram-positive and Gram-negative ones) were used in an experiment (Tab. I). All the tested strains inhibited the growth of at least one of the 13 indicator strains (Tab. II). The Enterococcus gallinarum EG 12 strain produced bacteriocin active to all the used indicator strains. The Enterococci EA 7, EG 12 and EG 10 inhibited the growth of the Gram-negative bacteria Providentia stuartii JH 1 and Escherichia coli EC 1. The Staphylococcus gallinarum SG 2 strain showed the lowest bacteriocin activity. Most strains showed medium-size zones (1 - 10 mm). The inhibitory zone of the Staphylococcus gallinarum SG 1 strain reached up to 10 mm. But the average size of the inhibitory zones ranged from 4 to 6 mm - Fig. 1. As to their morphological aspect, clear-cut inhibitory zones prevailed, only a few of them were less clear-cut to opaque zones.