## 4 Discussion  
Currently, 54 species of bacteria of the _Staphylococcus_ genus are known, and their number is increasing, as indicated by the addition of six more in the last 5 years [27]. Unlike many other bacterial pathogens, which often rely on one or a few toxins to develop disease, _S. aureus_ produces multiple virulence factors. These include both toxins and immune evasion factors, as well as proteinaceous and non-proteinaceous factors that enable host colonization during infection [28]. It is believed that persistent colonization of the intestines by _S. aureus_ may lead to gastrointestinal diseases and even systemic diseases because the intestine may constitute a reservoir for the distribution of _S. aureus_ to other sites of epithelial colonization [29; 30]. _S. aureus_ opportunistically exploits primary damage caused by other pathogens or predisposing factors [31; 32]. An important means of maintaining _S. aureus_ infection is the formation of biofilms [33]. They can form on abiotic material of permanently located medical devices, but also on tissue surfaces. The main role of biofilm formation during infection is to protect bacteria from phagocyte attacks [34]. Furthermore, _S. aureus_ biofilms have been shown to skew the host immune response towards an anti-inflammatory state [28; 34; 35]. The ability to form biofilm is an important virulence attribute due to its potential to induce persistent antibiotic resistance, delay phagocytosis, and attenuate or promote inflammation [36]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**CNS**} & \multicolumn{3}{c}{**CPS**} \\ \hline \multirow{2}{*}{**Strain**} & \multirow{2}{*}{**CRA**} & \multicolumn{2}{c}{**Spectrophotometric Method**} & \multirow{2}{*}{**Strain**} & \multirow{2}{*}{**CRA**} & \multicolumn{2}{c}{**Spectrophotometric Method**} \\ \cline{3-3} \cline{5-8}  & & **OD** & & **Result** & & **OD** & **Result** \\ \hline  
& 0.164 & \(-\) & 13/3 & N & 0.003 & \(-\) \\
37/1 & P & 0.689 & ++ & 72/1 & N & 0.003 & \(-\) \\
73/2 & N & 0.004 & \(-\) & 97/3 & N & 0.090 & \(-\) \\
61/1 & N & 0.032 & \(-\) & 41/3 & N & 0.015 & \(-\) \\
39/2 & N & 0.075 & \(-\) & 51/2 & N & 0.021 & \(-\) \\
13/1 & N & 0.175 & \(-\) & 97/1 & N & 0.090 & \(-\) \\
10/2 & N & 0.113 & \(-\) & 18/3 & P & 0.595 & ++ \\
36/3 & N & 0.157 & \(-\) & 75/3 & P & 0.676 & ++ \\ \hline \hline \end{tabular}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{4}{c}{CPS: coagulase-positive strain; CNS: coagulase-negative strain; CRA: Congo Red Agar test; N (negative): lack of ability of biofilm production demonstrated on CRA medium; P (positive): confirmed ability of biofilm production demonstrated on CRA medium; OD: optical density; + positive: confirmed ability of biofilm production demonstrated in the spectrophotometric test (+ weak); + moderate; ++ intensive): \(-\) negative: lack of ability of biofilm production demonstrated in the spectrophotometric test.  
\end{table} 
Table 5: Comparison of biofilm production results by CNS and CPS isolated from bulk tank milk. Antimicrobial resistance is an increasingly global problem around the world. The growth of drug-resistant virulent strains of _S. aureus_, especially methicillin-resistant _S. aureus_ (MRSA), is a serious problem in the treatment and control of staphylococcal infections [37; 38]. It should be remembered that bacteria of the genus _Staphylococcus_, and especially _S. aureus_ may be resistant, often in combination, to almost all available antibiotics [28]. _S. aureus_ is a microorganism ubiquitous in the milking parlor environment [39]. It was classified by [PERSON] et al. [40] as an infectious and environmental pathogen. This is because it spreads through various channels, such as litter, urine, feces, and other contaminants, as well as contaminated milk from infected cows or poor hygienic conditions during milking. Milk from _S. aureus_-infected dairy cows may be a continuing source of _S. aureus_ contamination of milking equipment and other surfaces.