## 4 Discussion
Subsequent surface colonization may lead to the eventual formation of a biofilm. The results published in 2023 by [PERSON] et al. [36] confirmed a statistically significant relationship between the occurrence of _S. aureus_ on monitored surfaces--the floor, teat cups, and milking equipment for cows-and the occurrence of mastitis caused by _S. aureus_. In our work, we showed that 73.3% of _Staphylococcus_ sp. strains isolated from milk can produce biofilm. These results are consistent with those of [PERSON] et al. [41], who showed that 72% of _S. aureus_ strains isolated from various food samples could produce biofilm. Like other research groups, we observed that both CPS and CNS strains have a similar ability to produce biofilm. The findings of the present study indicate that the smallest number of strains isolated from milk showed the ability to produce strong biofilm. Generally, this is consistent with results obtained on strains isolated from food. However, we observed an inverse correlation in the case of the ability to produce moderate and weak biofilm production. Our observations show that 53.57% of the tested strains showed moderate biofilm production and 17.8% showed poor biofilm production, while [PERSON] et al. [41] showed moderate biofilm production in only 14.43% of isolated strains and weak biofilm production in 54.64% of _S. aureus_ strains. Interestingly, studies conducted on _Staphylococcus_ sp. strains isolated from clinical cases showed that all (100%) have the ability to form biofilm [42]. While coagulase-positive _S. aureus_ (CPS) is often the subject of research because it is the predominant isolate in bovine mastitis milk [43], CNS strains both belonging to the _S. aureus_ species and other species of the _Staphylococcus_ genus (generally considered non-pathogenic) are of less interest to researchers. These bacteria, generally considered non-pathogenic, constitute a reservoir and a vector for transferring antibiotic resistance genes to subsequent populations of microorganisms. Bulk tank milk samples that meet veterinary requirements for milk intended for food are of even less interest to researchers. It is considered that this milk comes from healthy animals, so it is free from pathogens. However, it should be remembered that the term \"healthy animals\" is not equivalent to the term \"uninfected animals\". Therefore, it can and often happens that in a herd of dairy cows, there are individuals that shed bacteria of the _Staphylococcus_ genus into the environment. Therefore, due to their ability to colonize abiotic surfaces, these microorganisms are common in the environment, and being a reservoir of antibiotic-resistance genes, they may contribute to its growth in the microbial population [28; 36]. Resistant bacteria can therefore spread rapidly through milk to many hosts, including humans. It should also be remembered that such milk can be consumed by humans without thermal treatment to eliminate microbiological contamination (for personal use on the farm). In situations specified by law, milk may also be marketed as raw milk. Comparing the results obtained in the disk diffusion test to the presence of genes determining antibiotic resistance in the genome of the isolated strains, it was shown that all strains sensitive to ampicillin and vancomycin did not have them. In turn, resistance to antimicrobial substances demonstrated in the disk diffusion test was not correlated with the presence of genes determining antibiotic resistance in the genetic material of the isolated strains. This is probably because, in addition to specific, genetically determined resistance to antibiotics, bacteria of the _Staphylococcus_ genus have the ability to form biofilms, which generate non-specific resistance to antibiotics [33]. Most published works describe the antibiotic resistance profile of _Staphylococcus_ spp. strains isolated from mastitistis. Researchers have shown that _Staphylococcus_ spp.