Antimicrobial Efficacy of Cloxacillin-Loaded Chitosan Nanoparticles Against Staphylococcus aureus Biofilms in Subclinical Mastitis.

Bovine mastitis is the most widespread disease that causes financial loss in the dairy industry. Staphylococcus aureus is a well-researched multidrug-resistant opportunistic bacterium that is frequently linked to subclinical mastitis and causes significant economic losses. A further problem in the management of S. aureus infections is its capacity to form biofilms; bacteria inside biofilms exhibit greater resistance to antimicrobials than planktonic cells. The most effective method for controlling mastitis is antibiotic therapy. Cloxacillin (CLX), ampicillin, and ceftiofur are currently the most often utilized drying treatments for dairy cattle. We have evaluated the therapy efficiency of cloxacillin-loaded chitosan nanoparticles (CLX-CS NPs) as well as the relationship between biofilm production, gene profile and the type of trial group (CLX and CLX-CS NPs) against S.aureus isolated from milk samples of cows diagnosed with subclinical mastitis. Investigation of phenotypic biofilm production showed that majority of the S. aureus isolates extracted from milk were producers of biofilm. Cloxacillin-loaded chitosan nanoparticles were able to significantly decrease the MIC (p < 0.05) and MBC values compared to cloxacillin. The relationship between the gene profile and the types of trial groups shows that coating cloxacillin with chitosan nanoparticles (CS-NPs) was able to reduce the MIC and MBC value in all nine gene profile groups. These findings indicate that administration of cloxacillin-loaded CS-NPs in the treatment of mastitis may improve cloxacillin therapeutic properties and could act as a potential alternative to the cloxacillin antibiotic for the treatment of bovine mastitis.