Determination of genetic determinants of biofilm formation in isolates obtained from animals in the Omsk Irtysh region

Staphylococcus aureus is a major pathogen causing diseases in animals. About 60% of infections are caused by biofilms – organized bacterial populations consisting of extracellular matrix (ECM) and extracellular polymeric substances (EPS). Biofilm formation plays a key role in the development of chronic infections in livestock complexes. More than 80% of persistent infections are caused by biofilms, making treatment difficult. Biofilms protect bacteria from unfavorable environmental conditions and immune system responses. The biofilm formation process includes four stages: adhesion, aggregation, maturation, and dispersion. The aim of this work is to develop a test system for detecting virulence genetic determinants of Staphylococcus aureus – fnbB, icaD, and clfB, and to screen the distribution of these genes among isolates of S. aureus and Staphylococcus spp. isolated from agricultural and domestic animals, as well as from livestock infrastructure objects of enterprises in the Omsk region. The novelty of the work lies in the creation of a new real-time PCR-based test system for screening and detecting genetic determinants mediating biofilm formation. The study analyzed 11 isolates of S. aureus and 70 isolates of Staphylococcus spp. The fnbB gene was found in 18,2 % of S. aureus isolates and in 18,6 % of Staphylococcus spp. isolates. The icaD gene was found in 36,4 % of S. aureus isolates and 44,3 % of Staphylococcus spp. isolates. The clfB gene was found in 27,3 % of S. aureus isolates and 45,7 % of Staphylococcus spp. isolates. The combination of fnbB/ icaD genes was found in 18,2 % of S. aureus isolates and 17,1 % of Staphylococcus spp. isolates; the fnbB/clfB combination — in 18,2 % of S. aureus isolates and 18,6 % of Staphylococcus spp. isolates; the icaD/clfB combination — in 27,3 % of S. aureus isolates and 35,7 % of Staphylococcus spp. isolates. The combination of fnbB/icaD/clfB genes was found in 18,2 % of S. aureus isolates and 17,1 % of Staphylococcus spp. isolates.