Prevalence of Vancomycin-resistant Enterococcus in wild mammals: the first global systematic review and meta-analysis

Vancomycin-resistant Enterococcus (VRE) represents a global public health threat due to its ability to disseminate antimicrobial resistance (AMR) genes across ecological boundaries. While the prevalence of VRE has been extensively studied in clinical and agricultural settings, its occurrence and dynamics in wildlife remain underexplored. This review aimed to systematically examine and analyze the global prevalence of VRE in wild mammals.

Following PRISMA guidelines, an extensive search of six databases yielded 25 studies that met predefined inclusion criteria. Data were extracted and synthesized using a random-effects model to estimate pooled prevalence rates, and subgroup analysis was also performed. Heterogeneity was quantified using the I² statistic, and publication bias was assessed through funnel plots and Egger's test. The overall pooled prevalence of VRE in wild mammals was 8.4 % (95 % CI: 4.9-14.0), with significant heterogeneity (I² = 87.63 %). Southern Europe recorded the highest prevalence, particularly in Spain (18.6 %) and Portugal (7.0 %), while lower rates were observed in England (3.3 %) and Italy (4.5 %). Species-specific prevalence was highest in Eurasian otters and roe deer (62.1 % and 48.6 %, respectively). Methodological variability also influenced prevalence rates, with disc diffusion reporting the highest prevalence (17.3 %) compared to PCR-based methods (3.9 %).

The findings indicate a moderately significant prevalence of VRE in wild mammals, underscoring wildlife's critical role as reservoirs and vectors of AMR.

Anthropogenic factors such as agricultural activities and environmental pollution significantly shape the distribution and burden of VRE among wild animals.