Staphylococcus aureus Sbi and SpA proteins are important for host-control of early skin infections

GONZALEZ C; LEDO C; GOMEZ MI

Mar del Plata

Conferencia; LXII Reunión anual de la Sociedad Argentina de Inmunologia SAI; 2014

Staphylococcus aureus is an important human pathogen that causes infections with high morbidity and mortality. The protein A (SpA) and the Staphylococcal binding immunoglobulin protein (Sbi) are strong evasion factors. In addition, we have demonstrated their ability to induce the production of pro-inflammatory cytokines and chemokines in vitro and in vivo. This study was aimed at elucidating the contribution of SpA and Sbi to the development of abscess in a model of skin infection, in which an appropriate inflammatory response is known to be required to contain the bacteria. Mice were inoculated by subcutaneous route with 1x108 CFU of S.aureus strain Newman or the isogenic mutants that do not express Sbi (Sbi-), SpA (SpA-) or both (SpA-Sbi-). S.aureus caused abscesses with a median area of 0.70 cm2 (min 0.35; max 1.09), and a bacterial burden of 3.5x107 CFU (min 8x106; max 2.4x108) at day three after inoculation. Bacterial dissemination to the lung, spleen, liver and kidney was observed in more than 64% percent of the animals. The bacterial burden in the abscesses induced by the Sbi- mutant was significantly higher than that observed in S.aureus inoculated mice (p