Repurposing of non-steroidal anti-inflammatory drugs as adjunct therapies against biofilm-forming Staphylococcus aureus isolated from camel milk.

The emergence of antimicrobial resistance (AMR) due to biofilm-forming S. aureus is a worldwide issue associated with a variety of persistent infections, including mastitis. This study investigated the prevalence and molecular characterization of biofilm-forming S. aureus, risk factors associated with subclinical mastitis (SCM), and simulation-based computational modeling for biofilm-associated protein. Moreover, repurposing of non-steroidal anti-inflammatory drugs as adjunct therapies against biofilm-forming S. aureus was investigated in combination with antibiotics. Overall, 384 camel milk samples were collected and subjected to the California mastitis test (CMT), and 51.30% SCM prevalence was found in sampled animals. Among these, 59.39% of SCM-positive milk isolates were positive for S. aureus, while the prevalence of staphylococcal biofilm-positive isolates by Congo red agar (CRA) and tube method was 41.88% and 31.6%, respectively. Further, on genotypic investigation, 47.86% and 31.62% of isolates were found to have icaA and icaD genes, respectively. After this, biofilm-forming isolates were subjected to phylogenetic assessment, and results exhibited strong sequence identity of local icaA and icaD isolates with neighbouring countries. Moreover, phylogenetic analysis was further validated with simulation-based computational modeling by using different tools, and results depicted a close evolutionary relationship and predominant structural integrity of the icaA protein. Drug susceptibility profiling of biofilm-positive isolates showed high resistance against amoxicillin, trimethoprim+sulphamethoxazole, and cefixime. Furthermore, In-Vitro combination therapy trials showed synergistic effect of amoxicillin and trimethoprim+sulphamethoxazole with flunixin meglumine and cefixime with meloxicam. This study will provide baseline data on biofilm-forming S. aureus persistence in the camel population, along with devising an effective therapy against biofilm-forming S. aureus infections.