Detection of ebp (endocarditis- and biofilm-associated pilus) genes in enterococcal isolates from clinical and non-clinical origin

A collection of enterococci from clinical samples, fruits and vegetables, water and soil was investigated for the presence of endocarditis- and biofilm-associated pilus (ebp) genes by PCR amplification and also by colony hybridisation. A high percentage of Enterococcus faecalis clinical isolates (94.59%) as well as all isolates from fruits and vegetables and two of the three isolates from water and soil carried ebpA, ebpB and ebpC genes. For E. faecium, PCR amplification revealed that over 81.81% of isolates from water and soil carried the three genes, compared to the lower incidence detected among isolates from vegetables (68.42%) and clinical samples (33.33%). The remaining E. faecium isolates tested negative both in the PCR and hybridisation tests. This is the first report of ebp detection among non-clinical E. faecium. Comparative sequence analysis of ebp genes revealed a higher similarity of clinical isolate E. faecalis EH17 with E. faecalis V583, while the non-clinical isolates E. faecalis V30C2 and E. faecium A9C4 grouped in a separate cluster. Greatest differences among clusters were observed for ebpC gene. Results from the present study suggest that enterococcal populations adapted to specific environments may also differ in the sequences of pili-encoding genes. Such variations may be important to produce functional pili and may have direct implications on the adhesion and colonisation capacity of isolates.