Global prevalence of carbapenem- and colistin-resistant coliform isolates from wastewater: a systematic review and meta-analysis

Carbapenems and colistin are considered last-resort antibiotics for treating infections caused by multidrug-resistant (MDR) bacteria. The emergence of carbapenem- and colistin-resistant coliforms in wastewater (WW) poses a serious environmental and public health threat. This systematic review and meta-analysis aimed to estimate the global pooled prevalence of carbapenem-resistant (CRR) and colistin-resistant (CLR) coliforms isolated from various types of WW. We systematically searched PubMed, Scopus, and Web of Science up to October 2024 to identify eligible observational studies. Data synthesis was conducted using random-effects meta-analysis. Subgroup analyses were performed by continent, WW type, bacterial species, and sample size. Publication bias was assessed using funnel plots, Begg’s and Egger’s tests, and the trim-and-fill method, while heterogeneity was evaluated using Cochran’s Q test and the I 2 statistic. A total of 30 and 23 articles were included for CRR and CLR, respectively. Also, 4,990 and 3,589 coliform isolates were analyzed for CRR and CLR, respectively. The pooled prevalence of CRR coliforms was 35% (95% CI: 29–41; I2 = 98.9%), and CLR coliforms was 19% (95% CI: 14–23; I2 = 96.5%). The highest CRR prevalence was observed in Europe (43%; 95% CI: 22 – 63; I2 = 95.5%), and the highest CLR prevalence was reported in Asia (25%; 95% CI: 17 – 33; I2 = 95.3%). This study suggests that WW environments may serve as reservoirs for antibiotic-resistant coliforms. The observed prevalence of CRR and CLR coliforms in hospital and agricultural WW indicates a need for improved WW management, strengthened antimicrobial stewardship, and continued global surveillance within the One Health framework.