Current Insights On Household Reservoirs Of Methicillin-Resistant Staphylococcus Aureus
Methicillin-resistant Staphylococcus aureus (MRSA) transmission in healthcare settings has had extensive study.1 Institutions have established numerous policies and procedures to decrease transmission and resulting healthcare-associated MRSA (HA-MRSA) infections.2 In contrast, little research has examined transmission and the reservoirs of MRSA in the community that serve as sources of community-associated MRSA (CA-MRSA) infections.
Researchers have found that CA-MRSA infections recur in patients and also spread among households.3-5 The traditional belief was that colonization was a precursor to CA-MRSA infection. However, studies of CA-MRSA outbreaks have shown that MRSA also transmits in the environment both by skin-to-skin contact as well as contact with fomites.6,7 Initial strategies for both control and prevention of recurrent CA-MRSA infections and infections among household members and close contacts focused on nasal and skin decontamination.4 These strategies may be flawed, however, as they are based upon the theory that colonization precedes infection.
There has been limited research on household environmental contamination with MRSA. Studies have found S. aureus to colonize in household environments.8-10 Authors have reported MRSA contamination in 5 to 8 percent of houses with no CA-MRSA disease but in 26 to 32 percent of homes with CA-MRSA disease or homes of healthcare workers.8-10
Under experimental conditions, S. aureus can persist on household fomites for up to two months.6 Eells and colleagues recently examined the persistence of S. aureus in household environments.11 The authors found that S. aureus isolates frequently persisted in household environments for three months after a skin infection. They found a high contamination of fomites with S. aureus as well as a high prevalence of body contamination. Factors associated with environmental contamination included contamination of a household member, higher housing density and more frequent fomite cleaning. The authors suspected that fomite cleaning in this study was inadequate for decontamination of the environment as previous studies have shown that inadequate cleaning may be a means for dissemination of S. aureus into the environment.11,12
The household environment may serve as a persistent reservoir for recurrent and new infections in household members. Successful methods to prevent CA-MRSA infections may include decolonization of household environments in addition to household members. Patients should receive education on the role their home environment can play in recurrent and family member infections.
References
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2. Muto CA, Jernigan JA, Ostrowsky BE, et al. SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and enterococcus Infect Control Hosp Epidemiol. 2003;24(5):362-386.
3. Miller LG, Quan C, Shay A, et al. A prospective investigation of outcomes after hospital discharge for endemic, community-acquired methicillin-resistant and -susceptible Staphylococcus aureus skin infection. Clin Infec Dis. 2007;44(4):483-492.
4. Kaplan SL. Treatment of community-associated methicillin-resistant Staphylococcus aureus infections. Pediatr Infec Dis J. 2005;24(5):457-458.
5. Crum NF, Lee RU, Thornton SA, et al. Fifteen-year study of the changing epidemiology of methicillin-resistant Staphylococcus aureus. Am J Med. 2006;119(11):943-951.
6. Desai R, Pannaraj PS, Agopian J, Sugar CA, Liu GY, Miller LG. Survival and transmission of community-associated methicillin-resistant Staphylococcus aureus from fomites. Am J Infect Control. 2011;39(3):219-225.
7. Miller LG, Diep BA. Clinical practice: colonization, fomites, and virulence: rethinking the pathogenesis of community-associated methicillin-resistant Staphylococcus aureus infection. Clin Infect Dis. 2008;46(5):752-760.
8. Uhlemann AC, Knox J, Miller M, et al. The environment as an unrecognized reservoir for community-associated methicillin resistant Staphylococcus aureus USA300: a case-control study. PloS One. 2011;6(7):e22407.
9. Roberts MC, Soge OO, No D, Helgeson SE, Meschke JS. Characterization of Methicillin-resistant Staphylococcus aureus isolated from public surfaces on a university campus, student homes and local community. J Appl Microbiol. 2011;110(6):1531-1537.
10. Scott E, Duty S, Callahan M. A pilot study to isolate Staphylococcus aureus and methicillin-resistant S aureus from environmental surfaces in the home. Am J Infect Control. 2008;36(6):458-460.
11. Eells SJ, David MZ, Taylor A, et al. Persistent environmental contamination with USA300 methicillin-resistant Staphylococcus aureus and other pathogenic strain types in households with S. aureus skin infections. Infect Control Hosp Epidemiol. 2014;35(11):1373-1382.
12. Murphy CR, Eells SJ, Quan V, et al. Methicillin-resistant Staphylococcus aureus burden in nursing homes associated with environmental contamination of common areas. J Am Geriatr Soc. 2012;60(6):1012-1018.
