The global prevalence of biofilm-forming Enterococcus faecalis in clinical isolates: a systematic review and meta-analysis

Abstract

BACKGROUND: Enterococcus faecalis (E. faecalis) is a major cause of healthcare-associated infections (HAIs). It exhibits a strong biofilm-forming ability, which contributes to treatment resistance and persistence. Despite its clinical relevance, the global prevalence of biofilm-forming E. faecalis remains poorly defined. This study aimed to estimate the pooled prevalence of biofilm-forming E. faecalis in clinical isolates worldwide. METHODS: Following PRISMA 2020 guidelines, we systematically searched PubMed, Scopus, ScienceDirect, Google Scholar, and institutional repositories for studies published between 2015 and 2024. A total of 56 studies involving 3,739 clinical isolates met the inclusion criteria. We used a random-effects model to estimate pooled prevalence and conducted subgroup analyses based on WHO region, continent, publication year, specimen type, and biofilm detection method. Meta-regression and sensitivity analyses assessed heterogeneity and robustness. Publication bias was evaluated using Egger's test and corrected with trim-and-fill analysis. RESULTS: The global pooled prevalence of biofilm-forming E. faecalis was 68.68% (95% CI: 61.33-76.02%), with significant heterogeneity (I² = 99.30%). By WHO region, prevalence ranged from 57.93% (95% CI: 41.01-71.85%) in South-East Asia to 73.66% (95% CI: 63.40-83.92%) in the Eastern Mediterranean. By continent, South America (all from Brazil) showed the highest prevalence at 89.79% (95% CI: 73.02-106.56%). Studies from 2021 to 2024 reported higher prevalence (76.18%, 95% CI: 66.25-86.11%) than those from 2015 to 2020. Among specimens, urine showed the highest prevalence (80.47%, 95% CI: 61.17-99.77%). Among biofilm-positive isolates, 47.92% (95% CI: 39.34-56.51%) were strong producers. Meta-regression identified WHO region (p = 0.005) and specimen type (p = 0.043) as significant sources of heterogeneity. Egger's test indicated publication bias (p = 0.0066), but trim-and-fill analysis yielded a consistent adjusted prevalence of 68.08%. CONCLUSION: Biofilm formation is highly prevalent in E. faecalis clinical isolates globally, with substantial regional and specimen-based variation. These findings highlight the urgent need for standardized biofilm detection protocols, improved infection prevention and control, tailored antibiotic stewardship, and the development of anti-biofilm therapies to mitigate biofilm-associated resistance and enhance patient outcomes.