Patients with Staphylococcus aureus skin infection were more likely to experience a recurrence if the household fomites were contaminated with MRSA, according to new data.
“Our findings suggest that environmental decontamination, and perhaps not body decolonization, may be a key component of future successful S. aureus and MRSA prevention efforts,” the researchers wrote in Clinical Infectious Diseases. “Given the high rate of recurrent skin infections in our population, prospective trials of household environmental decontamination should be undertaken in order to improve our ability to prevent these extremely common and potentially life-threatening infections.”
Loren G. Miller, MD, MPH, associate professor of medicine at David Geffen School of Medicine, University of California, Los Angeles, and colleagues conducted a prospective, longitudinal cross-sectional study that included adults and children after they were treated for S. aureus skin infections, and their household contacts. Patients were identified from Chicago and Los Angeles. The researchers performed home visits for consenting patients within 21 days of study enrollment. The patients provided cultures from the nares and oropharynx and inguinal cultures. The researchers also swabbed common household fomites to test contamination. Repeat visits were performed at 3 months and 6 months.
Loren G. Miller
The study included 330 patients with more than one household follow-up visit: 119 patients had methicillin-sensitive S. aureus (MSSA) and 211 had MRSA. The most common infecting strain was USA300 MRSA, which was found in 182 patients. The study also included 588 household contacts: 282 were S. aureus colonized at more than one body site and 125 were colonized with MRSA.
Between the baseline and 3-month visit, 39% of the index patients reported a skin infection, and among the 287 that completed the 6-month follow-up, 33% reported a skin infection between months 3 and 6. In a multivariate analysis, there were two independent predictors of subsequent infection among index patients: hospitalization in the previous 3 months (OR=1.53; 95% CI, 1.09-2.15) and fomite contamination with MRSA (OR=1.61; 95% CI, 1.05-2.47).
Among the household contacts, 10% reported a skin infection at the 3-month follow-up visit. Among the 510 that completed the 6-month follow-up visit, 7% reported a skin infection between months 3 and 6. In a multivariate analysis, several independent predictors of infection were identified. Contacts at the Chicago site compared with the Los Angeles site were more likely to develop infection (OR=1.72; 95% CI, 1.07-2.77). Other risk factors included antibiotic exposure in the previous 12 months (OR=1.87; 95% CI, 1.18-2.96) and skin infection in the 3 months before the surveillance period (OR=7.31; 95% CI, 4.28-12.5).
“In contrast to expectations, nares, oropharynx, and inguinal S. aureus colonization was not associated with subsequent skin infection,” the researchers wrote. “While colonization is well established as a risk factor for subsequent S. aureus infection in hospitalized patients, its role as a predisposing factor for community-associated infection is far less clear.”
Disclosure: The researchers report no relevant financial disclosures.