ORIGINAL PAPER Assessment of environmental enterococci: bacterial antagonism, pathogenic capacity and antibiotic resistance Domenico Pangallo Æ Hana Drahovska ´ Æ Jana Harichova ´ Æ Edita Karelova ´ Æ Katarı ´na Chovanova ´ Æ Peter Ferianc Æ Ja ´n Turn ˇa Æ Jozef Timko Received: 8 April 2008 / Accepted: 22 July 2008 / Published online: 6 August 2008 Ó Springer Science+Business Media B.V. 2008 Abstract The properties of 166 environmental strains belonging to the seven enterococcal species were studied. Enterococci originated mainly from surface- and waste-waters. They were screened for the presence of enterocins, virulence factors, and antibiotic resis- tance. The presence of different enterocin genes (entA, entB, entP, ent31, entL50AB) was frequently observed in our enterococcal isolates, 109 strains contained at least one enterocin gene. The distribution of enterocin genes varied according to the species, the genes were present mainly in E. hirae and E. faecium. By enterocin spot assay, 10 isolates inhibited the growth of Listeria strains. To evaluate the pathogenic ability of isolates, the distribution of selected virulence genes (cylA, gelE and esp) was investigated, eleven strains were positive in some of these genes, five of them belonged to E. faecalis. Regarding the antibiotic resistance of isolates, only two strains were multiresistant and two strains (E. hirae and E. casseliflavus) were resistant to vancomycin. Keywords Environmental enterococci Á Enterocins Á Virulence factors Á Antibiotic resistance Introduction The genus Enterococcus is a heterogeneous group of bacteria which includes more than thirty different species. The interest on enterococci has been increased in the last decades mainly for two impor- tant characteristics: they are considered as infection agents especially in immunocompromised hosts and they are used as effective probiotics and as starter cultures in various fermented food (Maki and Agger 1988; Patterson et al. 1995; Agerholm-Larsen et al. 2000; Leroy et al. 2003; Manolopoulou et al. 2003). The relevance of enterococcal infections is mainly due to their high level of intrinsic and acquired antibiotics resistance (Mendez-Alvarez et al. 2000; Portillo et al. 2000; Shankar et al. 2002; Bujdakova et al. 2003; Kainer et al. 2007). Especially, nosocomial infections with multiresistant enterococcal strains pose serious medical problem actually solved in many hospitals worldwide. Though enterococci as opportu- nistic pathogens do not have strong virulence factors comparing with more virulent bacteria, several factors conferring the increase of virulence have been iden- tified in E. faecalis. The haemolytic cytolysin (Ike et al. 1990; Jett et al. 1994) lyses a broad range of eukaryotic and prokaryotic cells and it enhances the D. Pangallo (&) Á J. Harichova ´ Á E. Karelova ´ Á K. Chovanova ´ Á P. Ferianc Á J. Turn ˇa Á J. Timko Institute of Molecular Biology, Slovak Academy of Sciences, Du ´bravska ´ cesta 21, 84551 Bratislava, Slovak Republic e-mail: domenico.pangallo@savba.sk H. Drahovska ´ Á J. Turn ˇa Department of Molecular Biology, Faculty of Natural Sciences, Commenius University, Mlynska dolina B-2, 842 15 Bratislava 4, Slovak Republic 123 Antonie van Leeuwenhoek (2008) 94:555–562 DOI 10.1007/s10482-008-9272-9