One-year surveillance of methicillin-resistant Staphylococcus aureus nasal colonization and skin and soft tissue infections in collegiate athletes.

OBJECTIVE: To determine the frequency and clinical importance of methicillin-resistant Staphylococcus aureus (MRSA) colonization in student athletes. DESIGN: Prospective observational cohort study. SETTING: A major university in the southeastern United States. PARTICIPANTS: Student athletes participating in the men's football and women's lacrosse programs (N = 126). Main Exposure Monthly assessment of S aureus nasal colonization. MAIN OUTCOME MEASURES: Trends in S aureus colonization over time and the occurrence of skin and soft tissue infections. RESULTS: Methicillin-resistant S aureus nasal colonization varied significantly through the athletic season (4%-23%), peaking during times of highest athletic activity. This increase in colonization was not associated with the development of an outbreak of skin and soft tissue infections, and no single MRSA clone emerged as a dominant isolate. CONCLUSIONS: During the athletic season, there is a considerable burden of MRSA colonization in student athletes; however, colonization alone appears to be insufficient to trigger an outbreak of staphylococcal infections. A combination of distinct molecular characteristics in the organism and specific host factors may govern the development of staphylococcal disease.

Vaccination as infection control: a pilot study to determine the impact of Staphylococcus aureus vaccination on nasal carriage.

BACKGROUND: There is a critical need for an effective Staphylococcus aureus vaccine for the prevention of staphylococcal disease. In this study, we investigated the impact of S. aureus conjugate vaccine comprised of capsular polysaccharides 5 and 8 (CP5, CP8) on nasal colonization with S. aureus. METHODS: Healthy adults recruited from one academic medical center to participate in a lot consistency trial of StaphVAX (S. aureus capsular polysaccharide 5 and 8 conjugate vaccine) were assessed for S. aureus nasal colonization at two weekly points prior to vaccination and again at six weeks post-vaccination. Serum anti-capsular antibody titers to CP5 and CP8 were obtained prior to vaccination and 42 days post-vaccination and measured by ELISA. RESULTS: Thirty of 88 enrolled subjects (34%) had S. aureus isolated from at least one of the pre-immunization cultures. Of these, 20 were termed persistent carriers due to two positive cultures one week apart; 19 of the 20 were evaluable at Day 42. Baseline anti-CP8 concentrations were higher in persistent carriers of CP8+ S. aureus; however, baseline anti-CP5 levels were not significantly higher in individuals persistently colonized with CP5+ S. aureus. Statistically significant rises in antibody concentrations were noted after vaccination. At Day 42, 14 of 19 persistent carriers remained colonized; 5 subjects did not have evidence of S. aureus colonization. Ten additional subjects were positive for S. aureus at Day 42 who were not persistently colonized at baseline. Serum antibody concentrations were not statistically different between those with persistent carriage vs. those that lost carriage or those with newly acquired carriage. CONCLUSIONS: Immune responses to vaccine were brisk and comparable in subjects with or without persistent colonization. Despite a substantial rise in anti-CP5 and anti-CP8 antibody concentrations post-vaccination, S. aureus nasal colonization rates did not significantly change.

Increasing use of extracorporeal life support in methicillin-resistant Staphylococcus aureus sepsis in children.

BACKGROUND: Pediatric cases of fulminant community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections requiring extracorporeal life support (ECLS) have been reported, but the frequency of ECLS use for severe presentations of staphylococcal disease is unknown. OBJECTIVE: To describe the frequency and characteristics of children with MRSA infections requiring ECLS using local and international databases. METHODS: The reasons for use of ECLS in children 0-18 yrs of age were determined in both the Vanderbilt Children's Hospital medical record system and the Extracorporeal Life Support Organization database during the years 1994-2005. Demographic characteristics, ventilatory management, and measurements of cardiopulmonary status in subjects undergoing ECLS with a pre-ECLS diagnosis of infection with Staphylococcus aureus and MRSA were included. RESULTS: Three subjects with MRSA sepsis requiring ECLS were identified at Vanderbilt since 2000. Before that time, no cases due to MRSA were reported. The three subjects were previously healthy adolescents with severe necrotizing pneumonia associated with skin/soft-tissue infection and two died. A total of 45 patients requiring ECLS for MRSA infection were identified in the International Extracorporeal Life Support Organization database, with nearly half reported in the past 2 yrs (20 of 45 patients). The median age was 2.4 yrs (interquartile range, 0.36-14 yrs), with peaks noted in infancy and adolescence. In Extracorporeal Life Support Organization subjects with MRSA, survival to discharge was highest in infants and young children aged 1-4 yrs (65% and 71%, respectively) and lowest in the age ranges of 5-9 yrs and 13-18 yrs (0% and 31%, respectively). There were no statistically significant differences in pre-ECLS ventilatory settings, cardiopulmonary status, or frequency of complications between survivors and nonsurvivors. CONCLUSIONS: The use of ECLS for MRSA infection seems to be increasing both locally and internationally. High mortality rates, particularly in older patients, are concerning and highlight the increasing problem with this pathogen.