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Importance: The role of environmental contamination in recurrent Staphylococcus aureus infections within households and its potential effect on intervention strategies has been debated recently., Objective: To assess whether household environmental contamination increases the risk for recurrent infection among individuals with a community-associated methicillin-resistant S aureus (MRSA) infection., Design, Setting, and Participants: This cohort study was conducted from November 1, 2011, to June 30, 2014, in the Columbia University Medical Center catchment area. All patients within 72 hours of presentation with skin or soft-tissue infections and blood, urine, or sputum cultures positive for MRSA were identified. Two hundred sixty-two patients met study inclusion criteria; 83 of these (31.7%) agreed to participate (index patients) with 214 household members. Participants were followed up for 6 months, and 62 of the 83 households (74.7%) completed follow-up. Participants and researchers were blinded to exposure status throughout the study. Follow-up was completed on June 30, 2014, and data were assessed from July 1, 2014, to February 19, 2016., Exposure: Concordant environmental contamination, defined as having an isolate with the identical staphylococcal protein A and staphylococcal chromosomal cassette mec type or antibiogram type as the index patient's clinical isolate, present on 1 or more environmental surfaces at the time of a home visit to the index patient after infection., Main Outcomes and Measures: Index recurrent infection, defined as any self-reported infection among the index patients during follow-up., Results: One patient did not complete any follow-up. Of the remaining 82 index patients, 53 (64.6%) were female and 59 (72.0%) were Hispanic. The mean age was 30 (SD, 20; range, 1-79) years. Forty-nine of 61 MRSA infections where the clinical isolate could be obtained (80.3%) were due to the epidemic strain USA300. Among the 82 households in which a patient had an index MRSA infection, the clinical isolate was present in the environment in 20 (24.4%) and not found in 62 (75.6%). Thirty-five patients (42.7%) reported a recurrent infection during follow-up, of whom 15 (42.9%) required hospitalization. Thirteen recurrent infections were from the 20 households (65.0%) with and 22 were from the 62 households (35.5%) without environmental contamination (P = .04). Environmental contamination increased the rate of index recurrent infection (incident rate ratio, 2.05; 95% CI, 1.03-4.10; P = .04)., Conclusions and Relevance: Household environmental contamination was associated with an increased rate of recurrent infection. Environmental decontamination should be considered as a strategy to prevent future MRSA infections, particularly among households where an infection has occurred.

While much is known about the geographic distribution of different clonal types of methicillin-resistant Staphylococcus aureus (MRSA), few studies have assessed the molecular epidemiology of methicillin-susceptible S. aureus (MSSA), despite its continued clinical importance. In each U.S. Census region, reference laboratories collected successive MSSA isolates from patients with invasive or superficial staphylococcal infections for use in the Tigecycline Evaluation and Surveillance Trial. All isolates from the periods of 2004 to 2005 and 2009 to 2010 underwent antimicrobial susceptibility testing and characterization of their staphylococcal protein A (spa) type. Of the 708 isolates analyzed, 274 spa types were identified and divided into 15 genetic clusters. The most common clones were spa t002 (n = 63, 8.9%) and t008 (n = 56, 7.9%). While the distribution of the predominant spa types did not differ by U.S. Census region or time period, spa t008 was nearly twice as common in community skin and soft tissue infections than in nosocomial bloodstream infections (11.1% versus 5.6%, respectively; P = 0.008). Despite such differences, both community and nosocomial settings had diverse staphylococcal clonal types representing all major spa clusters. In contrast to those of MRSA, MSSA infectious isolates show wide genetic diversity without clear geographical or temporal clustering. Notably, the prevalent MSSA strains (spa t002 and spa t008) are analogous to the predominant MRSA clones, further demonstrating the importance of both lineages.