Small colony variants and their role in biofilm associated infections

Small colony variants (SCVs) are slow-growing bacterial subpopulations that play a critical role in chronic and biofilm-associated infections. SCVs arise due to metabolic and genetic adaptations, often involving mutations in electron transport and regulatory pathways, which contribute to their reduced growth rate, altered virulence factor expression, and increased biofilm formation. Their association with persistent infections in conditions such as cystic fibrosis, prosthetic joint infections, and bloodstream infections underscores the challenges they pose in clinical settings. Despite advancements in molecular characterization, SCVs remain difficult to detect and treat due to their phenotypic switching and resistance mechanisms. Therefore, this review explores the phenotypic and genotypic characteristics of SCVs across multiple bacterial species, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and other important bacterial pathogens. In addition, this article also highlights their role in antibiotic resistance, immune evasion, and persistence in host tissues. In essence, this article consolidates current findings on SCV pathophysiology, explores emerging diagnostic techniques, and discusses potential therapeutic strategies, emphasizing the need for targeted interventions to mitigate their clinical impact.