Prevalence of Methicillin-Resistant Staphylococcus aureus Colonisation in Patients Undergoing Total Joint Arthroplasty: A Retrospective Observational Study

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major contributor to surgical site infections (SSIs) and prosthetic joint infections (PJIs) following total joint arthroplasty (TJA). Colonisation with MRSA, particularly in the anterior nares, serves as an important endogenous source of postoperative infections. Patients undergoing arthroplasty are often elderly and have multiple comorbidities, making them particularly vulnerable to colonisation and subsequent infection. Early identification of MRSA carriers through preoperative screening provides an opportunity for targeted decolonisation strategies, which can significantly reduce postoperative complications, morbidity, prolonged hospital stay, and healthcare costs. Aim: To determine the prevalence of MRSA colonisation among patients undergoing total joint arthroplasty and to evaluate associated demographic and clinical risk factors. Material and Methods: This retrospective observational study was conducted at ICMR-NITVAR, Pune, over a period of 9 months. A total of 160 patients who underwent elective total joint arthroplasty (hip and knee) were included. Data were retrieved from hospital records, including demographic details, comorbidities, history of prior antibiotic use, and microbiological screening reports. Preoperative MRSA screening was performed using nasal and/or skin swabs. Isolation and identification of Staphylococcus aureus were carried out using standard microbiological techniques, and methicillin resistance was confirmed using the cefoxitin disc diffusion method according to CLSI guidelines. Statistical analysis was performed using SPSS software. Descriptive statistics were expressed as mean ± standard deviation and percentages. Inferential statistics were applied using Chisquare test or Fisher’s exact test, with a p-value <0.05 considered statistically significant. Results: Out of 160 patients, 18 were found to be colonised with MRSA, yielding an overall prevalence of 11.25%. A higher prevalence of MRSA colonisation was observed among patients aged ≥60 years (72.2%, p=0.041). Among comorbid conditions, diabetes mellitus (61.1%, p=0.032) and obesity (44.4%, p=0.048) showed significant associations with MRSA colonisation. A strong association was also observed with prior antibiotic use (66.7%, p=0.001) and previous hospitalisation (50.0%, p=0.045). Gender and hypertension did not demonstrate statistically significant associations. Conclusion: MRSA colonisation was observed in a considerable proportion of patients undergoing total joint arthroplasty. Advanced age, diabetes mellitus, obesity, prior antibiotic exposure, and previous hospitalisation were identified as significant risk factors. These findings highlight the importance of routine preoperative MRSA screening and targeted decolonisation protocols in high-risk patients to reduce postoperative infections and improve surgical outcomes.