Low necessity, high overuse: revisiting empirical vancomycin practices for children in low MRSA prevalence settings.

BACKGROUND: The overuse of vancomycin as empirical therapy ranged from 62% to 66% worldwide, while the prevalence of proven infections requiring vancomycin was only 11% to 27%. Evidence from Thailand where the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection is low and remains limited. This study aimed to determine the incidence of confirmed infections requiring vancomycin as definitive therapy among children aged 1 month-18 years receiving vancomycin as empirical therapy, and to identify factors associated with vancomycin necessity. METHODS: A single-centre retrospective cohort study was performed, which included 532 children receiving at least one dose of vancomycin as empirical therapy at a university hospital during 2014–2024. Demographic data, provisional diagnosis, ICU admission, haemodynamic status, presence of central venous catheters, and microbiological results were collected. Factors associated with proven infections requiring vancomycin were determined by multivariable log-binomial regression. RESULTS: Only 29 of 510 (5.68%) patients who had empirical treatment with vancomycin truly needed vancomycin as definitive treatment. Provisional diagnosis of device-associated infection, especially cerebrospinal fluid shunt (RR 6.97, 95%CI 2.92–16.63), and intra-abdominal infection following liver transplantation (RR 4.95, 95%CI 1.97–12.48), were significantly associated with proven infections requiring vancomycin in multivariable analysis. Febrile neutropenia, haemodynamic instability, and the presence of central venous catheters were not significantly associated with vancomycin necessity in univariate analysis. CONCLUSIONS: In a setting with a low prevalence of MRSA infection, most patients who received empirical vancomycin were subsequently found not to require it, highlighting the potential for more targeted empirical vancomycin use, such as patients with cerebrospinal fluid shunts or post-liver transplantation intra-abdominal infections.