Pathogenic analysis of Borrelia garinii strain SZ isolated from northeastern China

BACKGROUND: Various genospecies of Borrelia burgdorferi sensu lato (s.l.) have been identified from patients and animals worldwide. Genospecies-related dissemination of disease has been reported. The present study aimed to elucidate the pathogenicity of infections caused by B. garinii SZ isolated in China. B. burgdorferi B31 and B. afzelii BO23 were used for comparison. METHODS: Spirochete load in blood and tissue samples of infected mice were measured by minor groove binder-based real-time polymerase chain reaction. The kinetics of spirochete dissemination and disease severity were assessed in BALB/c mice. RESULTS: The pattern of bacterial load differed between the three genospecies. The B. garinii SZ strain is highly pathogenic and can trigger multi-system pathological damage in mice. CONCLUSIONS: Spirochete dissemination, persistence, tissue tropism and disease severity varied significantly, suggesting that different genospecies may play an important role in the pathogenicity and development of clinical diseases.