Colistin-resistance among <i>Acinetobacter baumannii</i> and <i>Pseudomonas aeruginosa</i> from clinical specimens in Africa: a systematic review and meta-analysis.

Abstract

<h4>Background</h4><i>Acinetobacter baumannii</i> and <i>Pseudomonas aeruginosa</i> are multidrug-resistant Gram-negative pathogens increasingly resistant to colistin, a last-resort antibiotic. This study estimated the pooled prevalence of colistin resistance among clinical isolates of these bacteria in Africa.<h4>Methods</h4>Relevant studies were retrieved from PubMed, Scopus, ScienceDirect and Google Scholar. Eligible studies reported colistin resistance in <i>A. baumannii</i> and <i>P. aeruginosa</i> from clinical specimens in Africa using EUCAST or CLSI standards. Data were analysed in STATA 17 using a random-effects model. Heterogeneity was assessed with the <i>I</i> ² statistic, and publication bias with Egger's test. Subgroup and sensitivity analyses explored heterogeneity sources.<h4>Results</h4>Twenty-five studies on <i>A. baumannii</i> and seventeen on <i>P. aeruginosa</i> were included. The pooled prevalence of colistin resistance was 13.75% (95% CI: 5.99%-21.51%), for <i>A. baumannii</i> and 14.42% (95% CI: 3.35%-25.48%) for <i>P. aeruginosa</i>, both showing high heterogeneity <i>I</i> ² > 99%. Resistance varied significantly across countries <i>P</i> ≤ 0.001. In <i>A. baumannii</i>, prevalence was 18.26% in Egypt and 10.89% in South Africa, with regional rates of 10.9%, 13.53% and 20.05% in Southern, North and East Africa, respectively. For <i>P. aeruginosa</i>, regional rates were 20.73% in East, 10.85% in North and 7.19% in Southern Africa. Resistance rose over time; from 5.64% to 16.45% in <i>A. baumannii</i> and from 2.26% to 30.54% in <i>P. aeruginosa</i> between 2010-2017 and 2018-2023.<h4>Conclusions</h4>Colistin resistance in <i>A. baumannii</i> and <i>P. aeruginosa</i> is rising across Africa, emphasizing the urgent need for robust antimicrobial stewardship, infection control and molecular surveillance.