title: Staphylococcus epidermidisProtection AgainstStaphylococcus aureusColonization in People Living With Human Immunodeficiency Virus in an Inner-City Outpatient Population: A Cross-Sectional Study.
abstract: BACKGROUND
  People living with human immunodeficiency virus (PLWH) have been disproportionally affected by methicillin-resistantStaphylococcus aureus(MRSA) colonization and infection, in particular by clones USA300 and USA500. However, the contribution of epidemiological, bacterial, and immunological risk factors to the excess ofS aureusin PLWH remain incompletely understood.
  
  
  METHODS
  In this cross-sectional study, we determined the prevalence and molecular epidemiology ofS aureuscolonization in 93 PLWH attending an urban human immunodeficiency virus (HIV) clinic. Participants completed a structured interview assessing demographic information and risk factors for MRSA. Swabs were obtained from the nose, throat, and groin and cultured forS aureusandStaphylococcus epidermidis.
  
  
  RESULTS
  Most participants had well controlled HIV infection (89, 96% CD4 >200). Thirty-six (39%) individuals were colonized withS aureusat 1 or more body sites, including 6 (6%) with MRSA. Regular gym use was a risk factor forS aureusbut not MRSA carriage. In contrast,S epidermidiswas present in almost all individuals (n = 84, 90%), predominantly in the nares (n = 66, 71%). Using generalized estimating equation models, we observed that the odds ofS aureuscolonization were significantly and drastically reduced whenS epidermidiswas detected (P= .0001). After controlling for site, gender, and age, we identified that the odds ofS aureuscolonization were 80% less ifS epidermidiswas present (adjusted odds ratio, 0.20; 95% confidence interval, .09-.45;P< .0001).
  
  
  CONCLUSIONS
  Taken together, we observed a lower prevalence ofS aureusand MRSA colonization than has been previously reported in PLWH. In this cohort, colonization withS epidermidiswas protective againstS aureuscolonization.
authors.affiliation: Departments of Medicine and.
authors.forename: Sean B
authors.initials: SB
authors.lastname: Sullivan
authors.affiliation: Departments ofMedicine and; Northwestern Memorial Hospital, Chicago, Illinois.
authors.forename: Suneel
authors.initials: S
authors.lastname: Kamath
authors.affiliation: Departments of Medicine and.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: McConville
authors.affiliation: Departments of Medicine and.
authors.forename: Brett T
authors.initials: BT
authors.lastname: Gray
authors.affiliation: Departments ofMedicine and; Pathology, Columbia University Medical Center, New York.
authors.forename: Franklin D
authors.initials: FD
authors.lastname: Lowy
authors.affiliation: Departments of Medicine and.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gordon
authors.affiliation: Departments of Medicine and.
authors.forename: Anne-Catrin
authors.initials: AC
authors.lastname: Uhlemann
keywords: HIV; MRSA; Staphylococcus aureus; Staphylococcus epidermidis.; immune dysregulation