Identification of plant-associated enterococci

Aims: Enterococcus isolates from forage grass were subjected to taxonomical investigations and tested for antibiotic resistance. Methods and Results: The identification procedure included phenotypic characterizations, restriction analyses of polymerase chain reaction-amplified 16S rDNA, whole-cell protein profile analyses and 16S rDNA sequence analyses. Agar diffusion tests were performed to detect antibiotic resistance. Conclusions: The isolates were identified as belonging to the species Enterococcus faecium, Ent. mundtii, Ent. casseliflavus, Ent. faecalis and Ent. sulfureus. However, the majority of isolates differed distinctly in their restriction patterns from those of known species. They formed a group of a homogeneous 16S rDNA genotype (VI). The 16S rDNA sequence of a representative isolate revealed the closest relationship to the species Ent. faecalis (similarity of 97.4%). All isolates were sensitive to vancomycin, but almost all were resistant to gentamycin and streptomycin. Significance and Impact of the Study: The taxonomical investigations suggest that the isolates of the 16S rDNA genotype VI represent a new plant-associated Enterococcus species.