Host Factors in Invasive and Recurrent Staphylococcus Aureus Infection

The incidence of community-associated (CA) staphylococcal infections, especially those caused by methicillin-resistant Staphylococcus aureus (MRSA), has increased dramatically in recent years. Although the majority of these infections are limited to the skin and soft tissue and thus not life threatening, the number of invasive cases in otherwise healthy individuals is increasing and some are fatal. As a first step toward understanding pathogenesis, there has been significant focus on elucidating the key CA-MRSA virulence factors. The relative significance of these factors is still being delineated. By comparison, there has been little focus on host factors associated with these invasive infections. In this protocol, we will recruit 100 otherwise healthy subjects with invasive staphylococcal infection, 50 otherwise healthy subjects with recurrent staphylococcal infections, and obtain samples from 150 unidentified healthy controls from the blood bank to investigate host immunologic factors predisposing people to staphylococcal infection. Subjects will receive standard of care treatment for acute or recurrent staphylococcal infections. The primary objective of this research is to identify host genetic factors that contribute to susceptibility or severity of community acquired staphylococcal diseases. We will use three experimental approaches to complete this objective: 1) expression microarray analyses of study population s (subjects and controls) white cells (neutrophils and peripheral blood mononuclear cells) at rest and stimulated with staphylococci, 2) evaluation of toll-like receptor (TLR) pathways in the study population s cells, and 3) evaluation of Th17 cells. The proposed research will address a key area of staphylococcal pathogenesis for which there is a striking lack of information. We fully anticipate that the research also will provide critical new information directly relevant to vaccine, diagnostics, and therapeutics development.