Correlation between carriers of Methicillin-resistant Staphylococcus aureus and the incidence of MRSA surgical site infections in orthopedic surgery patients.

Objective: Surgical site infection (SSI) is a devastating complication in orthopedic surgery. Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious organism in SSI, especially in orthopedic patients. We aimed to understand the association between MRSA carriers and the rate of SSI caused by MRSA in orthopedic patients.

Patients and methods: We prospectively performed a cohort investigation on patients admitted to the Department of Orthopedic between April and August 2023. Samples were taken preoperatively from the nose and post-operatively in surgical wounds. All samples were grown in MeReSa Agar and defined as positive with MRSA characteristics. Data analysis was performed using SPSS Statistics. A significant difference between groups was assessed using either the Chi-square test or Fisher's exact test. Statistical significance was set at p<0.05.

Results: We obtained 526 nasal swabs of patients, and 140 (26.6%) samples were positive for MRSA. Our study revealed significant associations between MRSA carriers and the following factors: history of recent hospitalization (OR: 1.81; 95% CI: 1.172-2.795; p=0.007), smoking history (OR: 1.55; 95% CI: 1.011-2.383; p=0.044), and antibiotic exposures (OR: 2.19; 95% CI: 1.305-3.703; p=0.003). Our findings showed a significant association between SSI and the following factors: history of antibiotic exposures (OR: 2.89; 95% CI: 1.264-6.566; p=0.003), blood loss volume >500 ml (OR: 2.522; 95% CI: 1.245-5.108; p=0.008) and contaminated surgical wounds (OR: 5.97; 95% CI: 2.907-12.266; p=0.001). Patients with MRSA carriers tended to have an increased risk of having an MRSA SSI with an odds ratio of 3.44 (95% CI: 1.13-10.48; p=0.047).

Conclusions: Our study highlights the increased risk of MRSA carriage in patients with a history of smoking, recent hospital admission, or antibiotic exposure. Our reports also identify potential risk factors for SSI, such as previous antibiotic exposure, blood loss, and contaminated wounds. Furthermore, our research establishes an association between MRSA colonization and MRSA SSI, which emphasizes the criticality of decolonization strategies. A further prospective multicenter study is needed to elaborate on our study findings.