Mastitis in dairy cows is a condition that is seen as being economically significant. The major pathogen in infectious bovine mastitis is known to be Staphylococcus aureus (S. aureus). The production of biofilms is a rising concern in human and animal health. Because of the minimal association between standard in vitro antimicrobial susceptibility to antimicrobial therapy efficacy, it was hypothesized that biofilm could play a significant role in the establishment of chronic S. aureus bovine mastitis. This research aims to isolate and characterize S. aureus strains from mastitic milk of bovine animals to evaluate biofilm formation by in vitro phenotypic tests like Congo red agar (CRA) and Microtitre plate (MTA) assay and molecular detection used to find specific biofilm-forming genes icaA (intercellular adhesion gene A) and icaD (intercellular adhesion gene D) and antimicrobial susceptibility testing. Traditional microbiology was used to isolate and identify S. aureus species, and the biofilmformin genes (icaA and icaD) were detected by polymerase chain reaction. A total of 60 mastitis milk samples were subjected to culture and isolation, out of which, 14 isolates were identified as S aureus. A sensitivity test for antimicrobial properties was performed on all the isolates in vitro using 16 antimicrobial agents. All isolates developed biofilms, with 9/14 (64%) strongly biofilm-forming, 3/14 (21%) moderately biofilm-forming, and 2/14 (14%) weakly biofilm-forming. The research demonstrated AMR, invasiveness, and biofilm formation in S. aureus isolated from bovine mastitis. This feature adds to the difficulties of current antibiotic therapy.

Highlights

• Isolation and characterization of S. aureus strains isolated from mastitic bovine animals.
• Assessment of the biofilm-forming and antimicrobial resistance ability of Staphylococcus aureus.