Health care-associated and community-associated methicillin-resistant Staphylococcus aureus infections: A comparison of definitions.
BACKGROUND
Different approaches are used to classify methicillin-resistant Staphylococcus aureus (MRSA) infections as either community-acquired (CA-MRSA) or health care-associated MRSA (HA-MRSA).


METHODS
We collected information on patients seen at the Atlanta Veterans Affairs Medical Center with MRSA infections from June 2007 through May 2008. We classified MRSA infections as either HA or CA using an epidemiologic definition and an antibiotic susceptibility phenotype rule. We used multivariate logistic regression to describe factors significantly associated with HA-MRSA infections compared with CA-MRSA infections.


RESULTS
Using the epidemiologic definition to classify infections, we found white race (odds ratio [OR], 3.2; 95% confidence interval [CI]: 2.0-5.2), oral antibiotics in the 3 months prior (OR, 4.0; 95% CI: 1.5-10.4), and endoscopy in the past year (OR, 3.8; 95% CI: 1.8-8.0) were significantly associated with health care-associated infections. When classifying by the resistance phenotype rule, we found hospitalization in the past year (OR: 1.8; 95% CI: 1.1-3.1) and an indwelling device in the past year (OR: 6.3; 95% CI: 2.5-15.8) were significantly associated with health care-associated infections.


CONCLUSIONS
We found few differences between CA- and HA-MRSA infections, regardless of how health care-association was defined. We believe that the migration of CA-MRSA into health care settings and the recent increasing antibiotic resistance of CA-MRSA strains contribute to the lack of factors associated with HA (vs CA) MRSA.
McCarthy
Natalie L
NL
Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Sullivan
Patrick S
PS
Gaynes
Robert
R
Rimland
David
D
D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D002404:Catheterization; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D003625:Data Collection; D004724:Endoscopy; D005845:Georgia / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D044469:Racial Groups; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology
D000900:Anti-Bacterial Agents