From Dormancy to Viability: The Resuscitation Processes of Viable but Non-Culturable Bacteria—A Systematic Review

Viable but non-culturable (VBNC) cells represent a reversible, metabolically active state that promotes the survival of bacteria under stressful conditions and their persistence in healthcare facilities and food industry. We conducted a systematic review following PRISMA 2020 guidelines to identify in vitro methodologies for inducing and resuscitating VBNC Enterobacteriaceae and <i>Pseudomonas aeruginosa</i>, and to determine key influencing factors. Eligible studies reported in vitro resuscitation of these species. Searches were performed in MEDLINE (PubMed), Scopus, and Google Scholar up to July 2025. Two independent reviewers screened and extracted data. Exclusion criteria included absence of original experimental data, focus on other species, or lack of clear VBNC definition. Risk of bias was qualitatively assessed. Analyses were descriptive without meta-analysis. Of the 1041 records, 24 articles (27 studies) were included. Resuscitation protocols typically employed standard culture media with additives and moderate incubation temperatures, with most successful recoveries occurring after 24-48 h. <i>P. aeruginosa</i> generally required less supplementation than Enterobacteriaceae. Reported mechanisms involved metabolic reactivation, oxidative stress modulation, nutrient sensing, and ribosome reactivation. The limitations of our study include protocol heterogeneity, lack of standardization, and selective reporting. While simple resuscitation methods were often effective, tailoring conditions to species-specific ecological preferences appears critical. Standardized approaches of VBNC cells will improve detection, risk assessment, and infection control.