Global and regional prevalence of metallo-β-lactamases in carbapenem-resistant Acinetobacter baumannii : a systematic review and meta-analysis

BACKGROUND: Emergence and spread of carbapenem-resistant Acinetobacter baumannii (CRAB) producing metallo-β-lactamases (MBLs), especially New Delhi MBLs (NDMs), are concerning due to resistance to last-resort antibiotics. METHODS: PubMed and Scopus were queried for studies published between 2020 and 2024 reporting MBL prevalence in CRAB isolates. Risk of bias was assessed across the population, setting and measurement domains. Binomial-Normal mixed-effects models were applied to estimate regional and country-specific weighted MBL and NDM prevalence proportions in CRAB. Subgroup and meta-regression analyses were performed to investigate heterogeneity. RESULTS: Two hundred thirty-three studies reporting 58 676 CRAB isolates were analysed. The global MBL prevalence in CRAB was 5.3% [95% confidence interval CI), 3.3%-8.2%]. Regional variability explained a substantial portion of heterogeneity in meta-regression (R2 = 35%). MBL prevalence in CRAB was highest in the Eastern Mediterranean (42.1%; 95% CI, 28.7%-56.8%) and African (36.1%; 95% CI, 12.2%-69.8%) regions, moderately high in South-East Asia (17.9%; 95% CI, 9.6%-30.9%), and low (