Prevalence of colistin-resistant Enterobacteriaceae isolated from clinical samples in Africa: a systematic review and meta-analysis

Abstract

BACKGROUND : Antimicrobial resistance among Enterobacteriaceae poses a significant global threat, particularly in developing countries. Colistin, a critical last-resort treatment for infections caused by carbapenem-resistant and multidrug-resistant strains, is increasingly facing resistance due to inappropriate use of colistin and the spread of plasmid-mediated resistance genes. Despite the significance of this issue, comprehensive and updated data on colistin resistance in Africa is lacking. Thus, the current study was aimed to determine the pooled prevalence of colistin-resistant Enterobacteriaceae in Africa. METHODS : A systematic search was conducted across PubMed, Scopus, ScienceDirect, and Google Scholar to identify relevant studies. Forty-one studies reporting on the prevalence of colistin resistance in Enterobacteriaceae isolates from clinical specimens in Africa were included in the analysis. Stata 17 software was used to calculate the pooled prevalence of colistin resistance, employing a random-effects model to determine the event rate of resistance. Heterogeneity across studies was assessed using the I2 statistic, and publication bias was evaluated using Egger’s test. Subgroup analyses were performed to address any identified heterogeneity. RESULTS : This systematic review analyzed the colistin resistance profile of 9,636 Enterobacteriaceae isolates. The overall pooled prevalence of colistin resistance was 26.74% (95% CI: 16.68–36.80). Subgroup analysis by country revealed significant variability in resistance rates, ranging from 0.5% in Djibouti to 50.95% in South Africa. Species-specific prevalence of colistin resistance was as follows: K. pneumoniae 28.8% (95% CI: 16.64%-41.05%), E. coli 24.5% (95% CI: 11.68%-37.3%), Proteus spp. 50.0% (95% CI: 6.0%-106.03%), and Enterobacter spp. 1.22% (95% CI: -0.5%-3.03%). Analysis based on AST methods revealed significant differences in colistin resistance rates (p = 0.001). The resistance rates varied between 12.60% for the disk diffusion method and 28.0% for the broth microdilution method. Additionally, a subgroup analysis of clinical specimens showed significant variation (p < 0.001) in colistin resistance. Stool specimen isolates had the highest resistance rate at 42.0%, while blood specimen isolates had a much lower resistance rate of 3.58%. CONCLUSIONS : Colistin resistance in Enterobacteriaceae is notably high in Africa, with significant variation across countries. This underscores the urgent need for effective antimicrobial stewardship, improved surveillance, and the development of new antibiotics.