MRSA spreads easily in household environments
Household environments play a significant role in the spread of MRSA in the community, according to a study of transmission events involving children with community-associated MRSA skin and soft tissue infections.
The study, published in The Lancet Infectious Diseases, showed that certain behaviors — such as sharing towels or personal hygiene items — increase the risk for colonization among household members.
“We know that even in high-risk settings such as hospitals, the frequency of hand-washing is suboptimal.” Stephanie A. Fritz, MD, MSCI, associate professor of pediatrics as Washington University School of Medicine in St. Louis, told Healio. “Yet, this simple practice can protect you from bringing MRSA into your home. Once these strains get in, they can take hold within the household niche and it is much harder to get rid of them, rather than preventing them from getting in to begin with.”
Fritz and colleagues recruited otherwise healthy pediatric patients with community-associated MRSA infections from hospitals and community practices in St. Louis. They excluded children who had evidence of a recent hospital admission, invasive medical device or residence in a long-term care facility. The researchers made a baseline visit and four quarterly visits to the patients’ homes over 12 months and collected cultures to detect Staphylococcus aureus from three anatomic sites of household members, two anatomic sites on cats and dogs and 21 environmental surfaces.
They observed 1,267 strain acquisition events among all household members, environmental surfaces and pets. The acquisitions were driven by 602 transmissions within households and 510 introductions of strains into households, according to the study.
Frequent handwashing was found to decrease the likelihood of novel strain introduction into the households (OR = 0.77; credibility interval [CrI], 0.63-0.94). Additionally, transmission recipients were more likely to share bedrooms with strain-colonized individuals (OR = 1.33; CrI 1.12–1.58), live in homes with higher environmental S. aureus contamination burden (OR = 3.97; CrI, 1.96–8.20) and report soft tissue and interval skin infection (OR =1.32; CrI, 1.07–1.64). Transmission sources were more likely to share towels (OR 1.25; CrI, 1.01–1.57), and although pets were often transmission recipients, they were rarely the sole transmission source.
Fritz emphasized that the study was limited to homes of children with MRSA infection.
“Sharing hygiene items such as bath towels may be safe in homes without MRSA,” Fritz said. “Also, all of these homes contain children, so results may not be generalizable to ‘adult only’ households.”
Fritz said they analyzed nearly 4,000 MRSA isolates during the study and were able to distinguish between strains “that had a foothold in the household before our involvement, and strains that were new to the households at visits that occurred over the year of follow-up.” Using these “fingerprints,” they were able to associate “distinct hygiene and behavioral factors associated with modes of acquiring MRSA, specifically introductions and transmissions.”
“Previous community-based MRSA prevention studies have focused solely on MRSA eradication of people through the use of topical antimicrobials and antiseptics,” Fritz said. “The findings of our study have informed the targets for intervention, and specifically, household environmental cleaning that may interrupt the transmission within these households.” – by Eamon Dreisbach
Disclosure: The authors report no relevant financial disclosures.