Trends in the Distribution and Antibiotic Resistance of Methicillin-Resistant Staphylococcus aureus in a Cancer Hospital from 2015 to 2024

Objective To monitor the distribution and antimicrobial resistance trends of Methicillin-resistant Staphylococcus aureus (MRSA) in a cancer hospital from 2015 to 2024. Methods Data from clinically positive specimens collected at Sichuan Cancer Hospital between 2015 and 2024 were analyzed, including patient demographics, departments, and microbiological susceptibility test results. The distribution and resistance trends of MRSA over the 10-year period were evaluated. Results Among 13,829 positive specimens, 1,550 Staphylococcus aureus isolates were identified, with a detection rate of 11.21%. Of these, 433 were MRSA, accounting for 27.94% of S. aureus isolates. The MRSA detection rate initially increased, peaking at 35.48% in 2018, followed by a gradual decline, though interannual differences were not statistically significant. The head and neck surgery ward had the highest number of MRSA detections and hospital-acquired infections, primarily surgical site infections. In contrast, the neurosurgery ward exhibited the highest MRSA detection rate. Regarding antimicrobial resistance, MRSA demonstrated universal resistance to ampicillin, penicillin, ampicillin/sulbactam, and oxacillin, while remaining universally susceptible to daptomycin, linezolid, tigecycline, and vancomycin(all resistance rates were 0%). Resistance rates to the other 12 antimicrobial agents fluctuated over time. Except for gentamicin and trimethoprim-sulfamethoxazole, MRSA exhibited higher resistance rates to most antimicrobials compared to Methicillin-Sensitive Staphylococcus aureus (MSSA). Conclusion Over the 10-year period, the MRSA detection rate in the cancer hospital remained high, fluctuating between 20% and 35%, without significant overall variation. MRSA resistance patterns showed some changes, with MRSA demonstrating broader and higher resistance rates compared to MSSA. Key departments should rationally select antimicrobial agents based on susceptibility results to mitigate the emergence and spread of resistant strains.