In-hospital antimicrobial use and multidrug-resistant infections among COVID-19 patients in Northern Malaysia (COVAM): a multicentre study

Background During the COVID-19 pandemic, empirical antimicrobials were frequently prescribed despite low documented rates of bacterial and fungal co-infections. While early pandemic data exist, evidence evaluating antimicrobial consumption and multidrug-resistant organism (MDRO) dynamics during subsequent pandemic surges remains limited. This study evaluated antimicrobial receipt, associated factors, and the prevalence of MDROs among hospitalised COVID-19 patients in Northern Malaysia.Methods This multicentre retrospective observational cohort study included adults (≥18 years) with confirmed COVID-19 admitted to ten government hospitals in Northern Malaysia between February 2020 and December 2021. Among 19,116 admissions, 480 cases were sampled, yielding 476 eligible patients. Study outcomes included antimicrobial receipt and MDRO prevalence. Monthly antimicrobial days of therapy (DOT) per 1,000 patient-days were compared with state-level COVID-19 hospital admissions. Predictors were analysed using a Poisson Generalized Linear Mixed Model.Results Antibiotics were prescribed to 167 patients (35.1%), accounting for 381 prescriptions, predominantly β-lactam/β-lactamase inhibitors (54.1%). Most were empirical (92.9%), largely among non-ICU patients (72.2%) with pneumonia (82.9%). Antifungals were used in 13 patients (2.7%; 15 prescriptions), mainly empirical echinocandins (60.0%), and predominantly in ICU settings (66.7%). MDROs were detected in 8.4% (10/119) of patients with cultured specimens, representing patient-level MDRO prevalence. A significant positive correlation was observed between DOT and admissions (r = 0.701, p < 0.001, 95% CI [0.37–0.87]). Severe/critical COVID-19 stage, diabetes mellitus, chronic obstructive pulmonary disease and chronic kidney disease were consistently associated with antimicrobial prescription. Longer hospital stays, elevated neutrophil and C-reactive protein levels, smoking, and pre-hospital steroid/immunosuppressant use were additional predictors.Conclusion Antimicrobial use was predominantly empirical and influenced by disease severity and admission surges. Although MDRO detection remained low, severity-driven prescribing highlights the risk of unnecessary antimicrobial exposure during pandemic waves. These findings inform outbreak-responsive antimicrobial stewardship strategies and support antimicrobial utilisation surveillance to guide resource planning during future public health emergencies.