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 Nov;35(11):1373-82. doi: 10.1086/678414. Epub 2014 Sep 22.


Objective: To understand the genotypic spectrum of environmental contamination of Staphylococcus aureus in households and its persistence.

Design: Prospective longitudinal cohort investigation.

Setting: Index participants identified at 2 academic medical centers.

Participants: Adults and children with S. aureus skin infections and their household contacts in Los Angeles and Chicago.

Methods: Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing.

Results: We enrolled 346 households, 88% of which completed the 3-month follow-up visit. S. aureus environmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistant S. aureus (MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject's infection isolate were body colonization by any household member with the index subject's infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75-20.79]), higher housing density (OR, 1.47 [95% CI, 1.10-1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16-2.27]). Household environmental contamination with the index subject's infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject's infection strain.

Conclusions: We found that infecting S. aureus isolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenic S. aureus strain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacterial Toxins / genetics
  • Bacterial Typing Techniques
  • Chicago
  • DNA, Bacterial / analysis*
  • Environmental Microbiology*
  • Exotoxins / genetics
  • Family Characteristics
  • Fomites / microbiology*
  • Genotype
  • Housing*
  • Humans
  • Leukocidins / genetics
  • Longitudinal Studies
  • Los Angeles
  • Methicillin-Resistant Staphylococcus aureus / classification
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Multilocus Sequence Typing*
  • Prospective Studies
  • Risk Factors
  • Staphylococcal Skin Infections / microbiology*
  • Time Factors


  • Bacterial Toxins
  • DNA, Bacterial
  • Exotoxins
  • Leukocidins
  • Panton-Valentine leukocidin