Effect of Bacteriocin-Like Substance Produced by Enterococcus faecium EF55 on the Composition of Avian Gastrointestinal Microflora

The influence of daily orally administered crude extract of bacteriocin-like substance (at a concentration of 3200 AU/ml) produced by Enterococcus faecium EF55 on the total counts of lactobacilli, staphylococci, enterococci and E. coli in the faeces and caecum of 3-day-old Japanese quails was investigated. Enterococcus faecium EF55 was isolated from the crop content of a chicken (Gallus domesticus). The inhibitory activity of bacteriocin-like substance (BLIS) produced by the strain EF55 was assayed by the agar spot test using Gram-positive and Gramnegative indicator bacteria. A wide range of Gram-positive genera such as Enterococcus, Staphylococcus, Micrococcus, Lactobacillus, Lactococcus, Streptococcus and Aerococcus was susceptible to BLIS, but none of the Gram-negative bacteria. The antimicrobial substance produced by the strain EF55 was thermo-resistant (30 min at 100 °C), stable at pH 4.0 to 9.0 at -20 °C, 4 °C and 22 °C for 10 d tested, and inactivated by proteolytic enzymes indicating its proteinaceous nature. After the first administration of bacteriocin crude extract (BCE) of EF55 strain to Japanese quails, a reduction amounting to 0.83-1.3 log cycles of E. coli, enterococci, staphylococci and lactobacilli in faeces was observed within 24 h. This inhibitory effect was most visible after first extract addition, later this difference was diminished. By agar spot test, BLIS produced by the strain EF55 of Ent. faecium was active against Staphylococcus spp., Lactobacillus spp. and Enterococcus spp., isolates obtained from the experimental birds. However, no inhibition against E. coli was detected, despite of their decreased counts under in vivo conditions. Bacteriocin, Japanese quails, gastrointestinal microflora, effec

Occurrence of Enterocin Genes in Enterococci from Slovak Milk Product Žinčica

Žinčica is a popular Slovak dairy product made from ewes’ milk. It is a by-product resulting during ewes’ lump cheese processing. Microbiota in Žinčica have rarely been studied, especially enterococci; however, they can produce beneficial substances – bacteriocins. In this study, the presence of Enterocins (Ents) genes were analysed in enterococci from Žinčica and partially also the inhibition activity. Samples of Žinčica were collected from different agrofarms producing ewes’ lump cheese (34) in Central Slovakia. In the enterococci tested, Ent P gene was the most frequently detected (in 6 out of 7 enterococci), followed by Ent A and Ent L50B genes. Ent B gene was detected only in E. faecium 30E1. On the other hand, E. faecalis 31E2 did not contain Ent genes, although it showed inhibition activity against the indicator strains Enterococcus avium EA5, Staphylococcus aureus SA5, Listeria monocytogenes CCM4699 (inhibition zone sizing up to 20 mm). E. faecium 30E1 contained genes of four Ents; however, it showed no inhibition activity. Growth of the four indicators was inhibited due to the antimicrobial activity of E. faecium 32E1 with Ent P gene detection. This is the first study reporting on the occurrence of Ent genes in enterococci from Žinčica