Analysis of the virulence potential, ability to form biofilms and susceptibility to bacteriocins of <i>Staphylococcus aureus</i> strains isolated from livestock and wildlife

Abstract Introduction The aims of the study were to analyse the ability of Staphylococcus aureus isolated from livestock and wildlife to produce biofilm, the presence of virulence genes and their distribution of within individual sequence types among these strains, and to assess the activity of bacteriocins isolated from Enterococcus and Lactococcus spp. against methicillin-resistant S. aureus (MRSA). Material and Methods Biofilm formation was assessed using the crystal violet assay. The occurrence of 29 virulence genes was examined by PCR. The analysis of the activity of 13 bacteriocins was carried out using the agar spot test. Results All the S. aureus strains had the ability to form biofilm. Nineteen virulence genes were detected, the most abundant of which were icaA, icaR, clfA and eno (all 100%), icaD (99%), icaB (85%), fnbpA (93%), cidA (87%), ebps (83%), sdrC (77%) and sdrE (76%). Correlations between the occurrence of clfB and fib and strong biofilm formation as well as between the occurrence of S eC, hla, hlb and fnbpB and methicillin resistance were observed (P-value &lt; 0.05). A high degree of heterogeneity in virulence profiles was observed in a host-dependent pattern. Among MRSA belonging mainly to sequence type 398, virulence profiles XII and XIII dominated, including several of the noted genes. The bacteriocins produced by L. lactis, E. asini and E. saccharolyticus had a growth-inhibiting effect on MRSA, nisin having the highest activity. Conclusion The presence of several virulence genes in the same S. aureus strain with demonstrable drug resistance and its ability to form biofilms indicate livestock and wildlife as potential reservoirs of pathogens dangerous to public health. The activity of some bacteriocins against MRSA could offer a promising alternative to antibiotic therapy.