PFGE analysis of enterococci isolates from recreational and drinking water in Greece

Biotyping and DNA fingerprinting by pulsed-field gel electrophoresis were applied to a collection of enterococci recovered from recreational and drinking water, in order to identify possible genetic relationships. Clinical strains of hospital origin were compared to the environmental isolates. A total of 104 enterococci were isolated from 128 recreational water (94 marine and 34 river water) and 470 drinking water supplies (440 municipal and 30 natural spring water samples). Sixty-two isolates were characterised as Enterococcus faecium recovered from all sources, 32 E. faecalis (from all sources), 4 E. durans (from marine, river and municipal water), 4 E. gallinarum (from marine water) and 2 E. avium (from marine and municipal water). Biotypes, determined with API20Strep, among E. faecium were correlated with certain environmental sources, while antibiotypes, determined with Etest, did not reveal any relationship to the sample origin. Even though genetic diversity was observed among the studied strains, common clonal types were also identified in different sources, suggesting a possible common origin of the enterococci. Cluster analysis revealed a genetic relationship between certain environmental E. faecium and clinical strains.