Imipenem resistance in Escherichia coli isolates from ICU patients: A systematic review and meta-analysis

Imipenem resistance in Escherichia coli within intensive-care settings (ICU) compromises effective empiric and targeted therapy and is associated with worse outcomes.

To quantify the global prevalence of imipenem-resistant E. coli (IR-EC) in ICU/NICU isolates, characterize between-study heterogeneity and temporal trends, and summarize distribution patterns by geography, health-system context, and laboratory methods.

We searched PubMed/MEDLINE, EMBASE, Scopus, and Web of Science from inception to 1 June 2025. Observational studies reporting IR-EC proportions (R/N) in ICU/NICU were included. Random-effects meta-analysis of proportions (variance-stabilized; back-transformed) was conducted. Heterogeneity (Q, τ², I²), subgroup analyses (country/WHO region, income level, AST method/guideline, period), and year-wise meta-regression were prespecified. Small-study effects were examined with Begg/Egger tests and Doi plot with LFK index; trim-and-fill assessed robustness. Risk of bias used the JBI prevalence checklist.

Forty-two studies comprising 15,227 isolates (752 resistant) were included from multiple countries and WHO regions. The pooled IR-EC prevalence was 9.5% (95% CI 5.6-15.7%; Q(41) = 1462.276, I² = 97.2%, p < 0.001). Trim-and-fill yielded 10.3% (95% CI 6.0-17.0%). Prevalence varied markedly: lowest in the United States (0.5%) and highest in Peru (85.7%). By WHO region, the Western Pacific pooled at 4.6% versus 38.4% in South-East Asia. By income level, lower-middle-income settings pooled at 32.5% versus 8.4% in upper-middle-income and 9.1% in high-income settings. Methodologically, broth microdilution studies pooled at 4.6% compared with disc diffusion 19.7% and automated systems 19.3%. Year-wise meta-regression indicated a significant upward trend (r = 0.113, p = 0.005, 95% CI 0.034-0.192). The Doi plot suggested major asymmetry (LFK = 4.84), while Begg (p = 0.651) and Egger (p = 0.867) were non-significant.

Imipenem-resistant E. coli affects about 10% of ICU/NICU isolates globally, with wide geographic and methodological variation and a significant rising trend over time. These results highlight the need for improved antimicrobial stewardship, standardized susceptibility testing, and enhanced molecular surveillance to guide empiric therapy in critical care settings.