Status: Funded - Closed
Invasive Staphylococcal disease in pediatric patients
Hillary Crandall, M.D., Ph.D.
BACKGROUND: Staphylococcus aureus is a common bacterial pathogen causing substantial morbidity and mortality in infants and children. Both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) can cause severe invasive disease. In many regions of the U.S., a particularly virulent strain of MRSA (USA300) has outcompeted other strains to become the primary cause of invasive infections, however MSSA continues to be the predominant cause of severe, invasive disease in the pediatric population in Utah.
GAP: The distinct epidemiology of severe invasive S. aureus disease in Utah offers a unique opportunity to better understand diverse factors contributing to the virulence of S. aureus, and to potentially identify novel virulence genes.
HYPOTHESIS: We hypothesize that specific clonal strains of MSSA are associated with invasive disease with increased severity of illness and/or distinct clinical characteristics. We expect that these strains will have unique virulence patterns or genes that correlate with severe disease presentations.
METHODS: This is a retrospective study of invasive S. aureus disease and associated bacterial isolates in a cohort of children treated for invasive infection at Primary Children’s Hospital.
RESULTS: Our preliminary work, based on isolates collected at Primary Children’s Hospital (PCH), has shown that invasive staphylococcal disease in our population has clinical characteristics consistent with severe MRSA disease; however, the majority of infections are caused by MSSA. Furthermore, most invasive S. aureus strains in our population are unrelated to USA300, and belong to clonal types different from those reported in other U.S. regions.
IMPACT: Although much is known about S. aureus virulence and spread, the molecular factors underlying the “success” of S. aureus as an invasive pathogen are far from being completely understood. This study offers a unique opportunity to better understand factors contributing to S. aureus virulence. Elucidation of factors closely associated with staphylococcal virulence could facilitate earlier identification and more effective treatment of pediatric patients with potentially life threatening infections, including the development of new diagnostic tests and potential therapies.