1130. Socioeconomic factors explain racial disparities in community-associated methicillin-resistant Staphyloccocus aureus disease rates
Session: Poster Abstract Session: MRSA/VRE Epidemiology
Friday, October 9, 2015
Room: Poster Hall

Background: Rates of methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States are higher among black than among white persons.  Since some socioeconomic factors are associated with MRSA infection and colonization, we explored the extent to which these factors might explain racial disparities in community-associated (CA) MRSA rates.

Methods: Data were obtained from active, population- and laboratory-based surveillance for invasive MRSA cases (isolated from normally sterile body site) from 33 counties in 9 states from 2009–2011.  Analyses included only CA cases (occurring as an outpatient or on day ≤3 of hospital admission in a patient without specified healthcare exposures [hospitalization, long-term care facility residence, surgery, or dialysis the prior year; or central venous catheter in 2 days prior to culture]).  Patients' residences were geocoded to census tracts, and tract-level socioeconomic indicators obtained from the American Community Survey.  A multivariate mixed Poisson model was used to determine the rate ratio (RR) of invasive MRSA infections in black compared to white persons, adjusting for tract-level socioeconomic status indicators.

Results: Of 2,722 CA MRSA cases, 2,521 (92.6%) were successfully geocoded.  The majority (75.6%) of cases were bloodstream infections.  Analyses by race were limited to black and white race (96% of cases).  Unadjusted MRSA incidence varied within counties (Figure), following some but not all racial population patterns.  Overall MRSA incidence was 4.59/100,000 white and 7.60/100,000 black persons.  After census-tract level adjustments for federally designated medically underserved areas, education, income, housing value, and rural status, the rate of community-associated MRSA among black persons was no longer elevated compared with white persons (RR: 1.00, 95% confidence interval, 0.90–1.10).

Conclusion: Socioeconomic factors measured at the census-tract level appear to account for higher rates of invasive CA MRSA infections in black persons.  The specific factors that underlie the association between tract-level socioeconomic measures and MRSA incidence, which may include modifiable social (e.g., poverty) and biological factors (e.g., acquired medical conditions), should be elucidated to define strategies for reducing racial disparities in MRSA rates.


Isaac See, MD1, Yi Mu, PhD1, Nicole Gualandi, RN, MS/MPH1, Ghinwa Dumyati, MD, FSHEA2, Lee H. Harrison, MD3, Ruth Lynfield, MD, FIDSA4, Joelle Nadle, MPH5, Susan Petit, MPH6, Claire Reisenauer, DVM7, William Schaffner, MD, FIDSA, FSHEA8, Amy Tunali, MPH9, Paul Wesson, BA10 and Jennifer Ahern, PhD10, (1)Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, (2)University of Rochester Medical Center, Rochester, NY, (3)Johns Hopkins Bloomberg Sch. of Publ. Health, Baltimore, MD, (4)Minnesota Department of Health, St. Paul, MN, (5)California Emerging Infections Program, Oakland, CA, (6)Connecticut Department of Public Health, Hartford, CT, (7)Colorado Department of Public Health and Environment, Denver, CO, (8)Department of Health Policy, Vanderbilt University School of Medicine, Nashville, TN, (9)Georgia Emerging Infections Program, Atlanta, GA, (10)University of California at Berkeley, Berkeley, CA


I. See, None

Y. Mu, None

N. Gualandi, None

G. Dumyati, None

L. H. Harrison, None

R. Lynfield, None

J. Nadle, None

S. Petit, None

C. Reisenauer, None

W. Schaffner, None

A. Tunali, None

P. Wesson, None

J. Ahern, None

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