Molecular Epidemiology and Dissemination of Extended-Spectrum Beta-Lactamases (ESBL)- producing Escherichia coli of European Wildlife: A Systematic Review and Meta-Analysis

Antimicrobial Resistance (AMR) in wildlife threatens public health globally, particularly concerning extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli). European wildlife populations can contribute to the dissemination and persistence of ESBL-producing E. coli in the environment. Our aim of study was to conduct a comprehensive analysis of E. coli and AMR profiles in the various wild birds and animals within the European continent. A systematic review and meta-analysis were conducted on studies published from 2000 onwards to 2025, focusing on ESBL-producing E. coli in wildlife across European countries. From more than 500 initially identified records, nearly 120 studies met the eligibility criteria, and 93 studies were included in the final quantitative synthesis. Pooled prevalence estimates were calculated using a random-effects model to estimate the inter-study variability. The comprehensive meta-analysis presented the pooled prevalence of 39.9% (95% CI: 31.1%-49.5%) for ESBL-producing Escherichia coli in the wildlife in Europe, with substantial heterogeneity among the studies included (I²=61.57%). Molecular characterisation indicated that bla_CTX-M, bla_TEM, bla_SHV and bla_CMY classes were the most frequently reported ESBL genes. Polymerase Chain Reaction (PCR)-based assays were the dominant diagnostic approach across studies, while more recent publications increasingly incorporated whole-genome sequencing (WGS), enabling detection of plasmid-associated resistance genes. A rising trend in publication output was observed over the last eight years, with the highest number of studies reported in 2021. While geographically, Italy accounted for the highest number of eligible studies. Wildlife populations in Europe represent an important reservoir of ESBL-producing Escherichia coli, with CTX-M-type enzymes predominating. The increasing use of genomic tools highlights the role of mobile genetic elements in cross-species dissemination. These findings support the need for coordinated One Health standardised monitoring and surveillance strategies across Europe to mitigate the consequences of AMR.