Molecular investigation of enterococci isolated from different environmental sources

Abstract

The properties of 61 environmental enterococci were studied. The strains were isolated mainly from surface and waste waters and several strains from sheep manure were also included. Species identification was provided by com-bination of phenotypic (Micronaut System, Merlin) and molecular detection methods (ITS-PCR, ddl-PCR and the whole cell proteins electrophoresis). A good agreement between molecular methods was observed, however, several discrepancies were observed when comparing molecular and biochemical iden-tification. Six enterococcal species were overall identified; E. faecium and E. hirae were the most abundant ones, almost 80 % of isolates belonged to these two species. E. faecalis, E. gallinarum and E. mundtii were detected in the case of several strains and both E. durans and E. casseliflavus were present ones. The distribution of selected genes conferring virulence to enterococci (cylA, gelE and esp) was studied; the positive signal was obtained only in four strains of E. faecalis. The strains were characterized also by detection of genes coding for enterocins – small secreted peptides with antibacterial activ-