Half of Enterobacterales Isolates Were ESBL-Positive in 2020–2024 Review, but Heterogeneity Limits Generalisability

A systematic review and meta-analysis published in Antimicrobial Resistance & Infection Control synthesised five years of evidence on extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), finding that ESBL production was common at the isolate level but that extreme between-study variation makes the pooled estimate descriptive rather than generalisable. Following PRISMA 2020 guidance and a PROSPERO registration (CRD420251001467), the researchers searched PubMed, MEDLINE, Scopus and Web of Science on 27 March 2025 for 2020–2024 studies reporting ESBL-E data from diagnostic specimens or colonisation screening across World Bank regions.

Of 140 eligible studies, 120 contributed prevalence data covering 18,691 isolates, of which 9,103 were ESBL-positive. The pooled prevalence was 50.37% (95% CI 45.79–54.95), but heterogeneity was extreme: I² was 97.30% and the 95% prediction interval spanned 8.00–92.00%. Certainty of evidence, assessed with an adapted GRADE approach alongside Joanna Briggs Institute risk-of-bias checklists, was low to very low, driven mainly by very serious inconsistency. In other words, individual studies reported results so divergent that the average should be read as a summary of the literature rather than a transferable figure for any given setting.

Regional pooled estimates ranged from 36.84% in Europe and Central Asia to 55.54% in East Asia and the Pacific, yet meta-regression detected no regional association (P = 0.58; R² = 0.00), meaning the apparent geographic spread was not statistically supported. Detection method was the only significant prevalence moderator (P = 0.004), with genotypic detection yielding a pooled prevalence of 73.93% versus 47.09% for phenotypic methods; the authors stress this was an exploratory study-level contrast rather than a paired isolate-level comparison, so it cannot show that the same isolates test differently by method.

On molecular epidemiology, CTX-M enzymes predominated among ESBL producers. The proportion of blaCTX−M−15 varied significantly by region (P < 0.001), from 20.11% in East Asia and the Pacific to 89.00% in the Middle East and North Africa. Unlike the prevalence findings, this regional signal was retained in the authors’ exploratory analysis, making gene distribution one of the more robust descriptive patterns in the review.

Co-resistance was widespread. Resistance to fluoroquinolones ranged from 55.23% to 63.27% across analyses, and resistance to trimethoprim/sulfamethoxazole reached 74.54%. Species-specific patterns also emerged: Klebsiella pneumoniae showed higher pooled resistance than Escherichia coli, including to carbapenems (20.06–37.68% versus 6.17–8.80%), although the authors note the species were not formally compared statistically. Carbapenem resistance may reflect additional mechanisms beyond ESBL production, because carbapenemase status was rarely confirmed in the underlying studies.

The authors’ conclusion is deliberately cautious. ESBL production was common in the isolate-level evidence, but extreme heterogeneity limits generalisability, and the high co-resistance they observed supports locally interpreted surveillance and context-specific antimicrobial stewardship rather than blanket policies. These descriptive findings, they write, should not be used as stand-alone clinical guidance. The review fills a gap the authors identified in earlier literature: previous reviews focused on specific populations, species or regions, while surveillance platforms often omit gene distribution, detection-method variability and species-specific resistance, all of which proved consequential here.

Subject of Research: Prevalence, molecular epidemiology and antibiotic resistance of ESBL-producing Enterobacterales, 2020–2024

Article Title: Prevalence, molecular epidemiology and antibiotic resistance of extended-spectrum β-lactamase-producing Enterobacterales (2020–2024): a systematic review and meta-analysis of regional and between-study variation

Article References: Krisniawati, N., Daniwijaya, E. W., Prasetyoputri, A., Ahmad, R. A., & Nuryastuti, T. (2026). Prevalence, molecular epidemiology and antibiotic resistance of extended-spectrum β-lactamase-producing Enterobacterales (2020–2024): a systematic review and meta-analysis of regional and between-study variation. Antimicrobial Resistance & Infection Control. https://doi.org/10.1186/s13756-026-01837-1

Image Credits: AI Generated

DOI: 10.1186/s13756-026-01837-1

Keywords: ESBL, Enterobacterales, antimicrobial resistance, meta-analysis, CTX-M, Klebsiella pneumoniae, Escherichia coli, carbapenem resistance, surveillance, systematic review, Prevalence, molecular