Isolation and identification of a Staphylococcus aureus small colony variants

Abstract:

Abstract: [Objective] Staphylococcus aureus small colony variants (S. aureus SCVs) could lead to persistent, recurrent infection with the characteristics of aminoglycosides antibiotics resistance, making them a big challenge for clinical diagnosis and therapy. We aimed at isolating and identifying isolates of S. aureus SCVs and providing the biological material of SCVs study in China. [Methods] The combination assays of observing colony phenotype, identification of the species-specific gene nuc of S. aureus by PCR amplification and a series of biochemical tests were conducted on 104 clinical isolates originally isolated from human, cow and environment. The suspected isolates were confirmed as S. aureus SCVs by complementation assay with supplementation of menadione, thiamine, thymine and haemin. [Results] One of the isolates from environment was identified as SCVs, named CDC54 with the species-specific gene nuc of Staphylococcus aureus (S. aureus) confirmed by PCR amplification, whose major phenotypes included smaller colony, decreased pigmentation, decreased coagulase, reduced fermentation of lactose, decreased haemolytic activity, increased resistance to aminoglycosides.[Conclusion] The CDC54 will play an important role in studying prevention, control and pathogenesis for S. aureus SCVs infection.