Global and regional prevalence of metallo-β-lactamases in carbapenem-resistant Acinetobacter baumannii: a systematic review and meta-analysis
Our latest research paper was published in the Journal of Antimicrobial Chemotherapy (British Society for Antimicrobial Chemotherapy) on 5 February 2026.
Global and regional prevalence of metallo-β-lactamases in carbapenem-resistant Acinetobacter baumannii: a systematic review and meta-analysis
by
Stamatis Karakonstantis, Renatos Nikolaos Tziolos, Maria Paneta, and Evangelos I Kritsotakis
Abstract
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 (<1%) in Europe, the Americas and the Western Pacific region. MBL prevalence in CRAB was higher in studies conducted during 2020–2024 than during 2012–2019 (7.2% versus 4.2%; adjusted odds ratio 2.3, P = 0.024). NDM was the dominant MBL in CRAB, with a global prevalence of 1.7% (95% CI, 1.1%–2.7%) in 218 studies.
Conclusions: Although its global prevalence is low, MBL-producing CRAB is common in specific regions and countries, threatening the utility of new antibiotics. Sustained surveillance, rigorous infection control and antimicrobial stewardship are required to preserve the activity of last-resort antimicrobials.
Keywords: Acinetobacter baumannii, Carbapenemases, Metallo-β-lactamases, Global epidemiology, Drug resistance, Prevalence.
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Figure 4. Global distribution of the country-specific estimates of the prevalence of MBL- and NDM-producing carbapenem-resistant A. baumannii clinical isolates.
Figure 3. Time trend in the annual global prevalence of MBL- and NDM-producing CRAB isolates. The bubbles represent data points from individual studies; their sizes are proportional to sample sizes. A restricted cubic spline was used to model the independent effect of the year of study conduct on the proportions of MBL CRABs (solid blue line) and NDM CRABs in particular (solid red line) in a multivariable Binomial-Normal mixed-effects model, adjusting for WHO region, multicounty setting, multicentre setting and risk of bias classification. The bluish-grey and violet shaded areas represent the corresponding pointwise 95% confidence intervals. MBL, metallo-β-lactamase; NDM, New Delhi MBL; CRAB, carbapenem-resistant A. baumannii.
