Antibiotic resistance and biofilm formation in Staphylococcus aureus isolated from dairy cows at the stage of subclinical mastitis in northern Kazakhstan

is an important causative agent of subclinical bovine mastitis worldwide. The aim of this research was to study the ability of to form biofilms. Additionally, we examined the genes involved in cell resistance and sensitivity to antibiotics. Samples were collected from December 2020 to May 2021 from Simmental and black-and-white cows. The study was carried out on a total number of 643 cows, of which 278 (23 %) were in the subclinical mastitis stage. Finally, 64 isolates were isolated and identified. The highest level of phenotypic resistance was observed to antibiotics of the tetracycline (tetracycline - 48.4 %, doxycycline - 32.8 %) and -lactam (ampicillin - 45.3 %, penicillin - 45.3 %) groups. The genes encoding antibiotic resistance were characterized with the polymerase chain reaction method: in 30 isolates, in 1 isolate, in 15 isolates, (3) in 2 isolates, in 19 isolates, in 9 isolates. The tested isolates had the ability to form biofilms in 76.6 % ( ) of cases. Of these, 69.4 % were resistant to at least one antibiotic. The obtained results have shown that , identified in cows with subclinical mastitis, was resistant mainly to tetracycline and -lactam antibiotics. In addition, isolates expressed resistance genes to the above drugs and had the ability to form biofilm. This study will help to identify the extent of antibiotic resistance and monitor contamination of raw milk.