Biofilm-forming ability and virulence factor detection in Enterococcus hirae strains of canine origin

Bacteria, including enterococci, occur and exist in biofilm which is more favourable for them than existence in a planktonic form. In this study, 28 faecal canine strains of the species E. hirae were assessed to have virulence factor genes when studying their antibiotic status (susceptibility and/or resistance) but also their biofilm-forming ability, to assess their pathogenic potential. Biofilm-forming ability was associated with the presence of the intercellular adhesion gene cluster (ica) mediating the production of the polysaccharide intercellular adhesion. The bap gene (for biofilm-associated protein) encodes a protein associated with the cell wall. Only E. hirae CH+P/2a possessed the ica gene (for biofilm production) but the strains did not possess the bap gene. However, regarding the biofilm-forming ability testing using a quantitative method, 16 out of the 28 E. hirae showed low-grade positive biofilm-forming ability. Twelve strains did not form a biofilm. In two strains (EH/CH10b, EH/CH+P/4a), the adhesin gene efaAfm was found, and also esp and gelE genes (for surface protein and gelatinase). Gentamicin was the most effective antibiotic against canine E. hirae strains (100% susceptibility). On the other hand, the highest resistance (57.1%) was recorded in the case of ampicillin. Following assessment of E. hirae in this study, it was found that they did not show pathogenic potential.