Staphylococcus aureus small-colony variants: Formation, infection, and treatment

Staphylococcus aureus (Sau) plays an important role in human infections occurring in both the community and hospital settings. Sau-related chronic and relapsing infections are mainly attributed to small-colony variants (SCVs), a type of subpopulation that has a size one-tenth that of normal colonies and is accompanied by several unique characteristics, including a lack of or reduced pigmentation, decreased hemolytic activity, increased biofilm formation, enhanced resistance to antimicrobials, upregulated genes encoding adhesion molecules, and downregulated genes for virulence factors. This review summarizes the significance of genetic mutations involved in diverse biosynthesis pathways that contribute to Sau-SCV promotion. Sau-SCV-caused persistent infections and the prospects and challenges faced in the treatment of Sau-SCV infections are addressed. Progress in the management of Sau-SCVs may provide guidance for addressing the long-term and recurrent infections caused by other bacterial SCVs.