Concurrent Epidemics of Skin and Soft Tissue Infection and Bloodstream Infection due to Community-associated Methicillin-Resistant Staphylococcus aureus.
Clin Infect Dis. 2012 Jun 5;
Authors: Tattevin P, Schwartz BS, Graber CJ, Volinski J, Bhukhen A, Bhukhen A, Mai TT, Vo NH, Dang DN, Van Phan TH, Basuino L, Perdreau-Remington F, Chambers HF, Diep BA
Background.?Since its emergence in 2000, epidemic spread of the methicillin-resistant Staphylococcus aureus (MRSA) clone USA300 has led to a high burden of skin and soft tissue infection (SSTI) in the US, yet its impact on MRSA bloodstream infections (BSI) is poorly characterized.Methods.?To assess clonality of the MRSA isolates causing SSTI and BSI during the epidemic period, a stratified, random sample of 1,350 from a total of 7,252 unique infection isolates recovered at the Community Health Network of San Francisco from 2000 to 2008 were selected for genotyping. Risk factors and outcomes for 549 BSI cases caused by the USA300 epidemic clone and non-USA300 MRSA clones were assessed by retrospective review of patient medical records.Results.?From 2000 to 2008, secular trends of USA300 SSTI and USA300 BSI were strongly correlated (Pearson's r correlation = 0.953). USA300 accounted for 55% (304/549) of BSI as it was the predominant MRSA clone that caused community-associated (115/160), healthcare-associated community-onset (125/207), and hospital-onset (64/182) BSI. Length of hospitalization after BSI diagnosis and mortality rates for USA300 and non-USA300 were similar. Two independent risk factors for USA300 BSI were identified: concurrent SSTI (adjusted relative risk, 1.4, [95% CI, 1.2 to 1.6]) and anti-MRSA antimicrobial use in the preceding 30 days (0.7 [0.6 to 0.8]). Isolates from concurrent SSTI were indistinguishable genotypically from the USA300 isolates that caused BSI.Conclusions.?USA300 SSTI serve as a source for BSI. Strategies to control USA300 SSTI epidemic may lessen severity of the concurrent USA300 BSI epidemic.
PMID: 22670044 [PubMed - as supplied by publisher]