Prevalence of Staphylococcus aureus nasal colonization in the United States, 2001-2002.
BACKGROUND
Staphylococcus aureus is a common cause of disease, particularly in colonized persons. Although methicillin-resistant S. aureus (MRSA) infection has become increasingly reported, population-based S. aureus and MRSA colonization estimates are lacking.


METHODS
Nasal samples for S. aureus culture and sociodemographic data were obtained from 9622 persons > or = 1 year old as part of the National Health and Nutrition Examination Survey, 2001-2002. After screening for oxacillin susceptibility, MRSA and selected methicillin-susceptible S. aureus isolates were tested for antimicrobial susceptibility, pulsed-field gel electrophoresis clonal type, toxin genes (e.g., for Panton-Valentine leukocidin [PVL]), and staphylococcal cassette chromosome mec (SCCmec) type I-IV genes.


RESULTS
For 2001-2002, national S. aureus and MRSA colonization prevalence estimates were 32.4% (95% confidence interval [CI], 30.7%-34.1%) and 0.8% (95% CI, 0.4%-1.4%), respectively, and population estimates were 89.4 million persons (95% CI, 84.8-94.1 million persons) and 2.3 million persons (95% CI, 1.2-3.8 million persons), respectively. S. aureus colonization prevalence was highest in participants 6-11 years old. MRSA colonization was associated with age > or = 60 years and being female but not with recent health-care exposure. In unweighted analyses, the SCCmec type IV gene was more frequent in isolates from participants of younger age and of non-Hispanic black race/ethnicity; the PVL gene was present in 9 (2.4%) of 372 of isolates tested.


CONCLUSIONS
Many persons in the United States are colonized with S. aureus; prevalence rates differ demographically. MRSA colonization prevalence, although low nationally in 2001-2002, may vary with demographic and organism characteristics.
Kuehnert
Matthew J
MJ
National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. mkuehnert@cdc.gov
Kruszon-Moran
Deanna
D
Hill
Holly A
HA
McQuillan
Geraldine
G
McAllister
Sigrid K
SK
Fosheim
Gregory
G
McDougal
Linda K
LK
Chaitram
Jasmine
J
Jensen
Bette
B
Fridkin
Scott K
SK
Killgore
George
G
Tenover
Fred C
FC
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001427:Bacterial Toxins / Q000235:genetics; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005006:Ethnicity; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D009666:Nose / Q000382:microbiology*; D015995:Prevalence; D012737:Sex Factors; D012959:Socioeconomic Factors; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000254:growth & development* / Q000302:isolation & purification; D014481:United States
D001427:Bacterial Toxins; D004269:DNA, Bacterial