A U.S. population-based survey of Staphylococcus aureus colonization

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• The epidemiology of Staphylococcus aureus (S. aureus) colonization, including community-associated methicillin-resistant Staphylococcus aureus (MRSA), is dynamic and national data are limited.
• Understanding current trends in S. aureus nasal carriage is crucial for public health interventions.

Purpose of the Study:

• To characterize the U.S. epidemiology of S. aureus nasal colonization.
• To compare risk factors for colonization with methicillin-sensitive S. aureus (MSSA) and MRSA.
• To analyze antibiotic resistance patterns and genetic factors of colonizing S. aureus strains.

Main Methods:

• Secondary analysis of the National Health and Nutrition Examination Survey (NHANES) data from 2001-2002.
• Inclusion of noninstitutionalized U.S. participants over 1 year of age.
• Assessment of S. aureus and MRSA colonization prevalence, risk factors, antimicrobial resistance, and genetic markers.

Main Results:

• S. aureus colonization prevalence was 31.6%, with MRSA at 0.84% nationally.
• Risk factors for S. aureus colonization included younger age (<65), male sex, lower education, and asthma; lower risk was observed in black individuals and those of Mexican birth.
• MRSA colonization was more prevalent in older adults (≥65), women, individuals with diabetes, and those with recent long-term care; Hispanic individuals had lower risk than white individuals.
• MRSA isolates with staphylococcal chromosomal cassette mec type IV were more sensitive to erythromycin, clindamycin, and ciprofloxacin.

Conclusions:

• Distinct characteristics and risk factors differentiate MSSA and MRSA colonization.
• Findings suggest that colonizing S. aureus strains may differ from those causing infection, and identified risk factors may not directly translate to invasive disease.
• While the 2001-2002 NHANES data provide valuable insights, they may not reflect current epidemiological shifts; however, they remain the sole national dataset available.