Incidence of and risk factors for clinically significant methicillin-resistant Staphylococcus aureus infection in a cohort of HIV-infected adults.
OBJECTIVE
Outbreaks of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) have been noted in multiple sites in the United States. This study's purpose was to estimate trends in the incidence of and risk factors for clinically significant MRSA (CS-MRSA) infection in a cohort of HIV-infected adults.


METHODS
A retrospective clinic-based cohort (January 1, 2000-December 31, 2003) study.


METHODS
We ascertained all initial episodes of CS-MRSA and categorized them by primary site. Incidence rates were estimated by half year. Risk factors for CA-MRSA infection were identified using Cox modeling.


RESULTS
Of 126 potential events, 94 were CS. Their primary sources were 83% skin or soft tissue, 10% blood, 6% respiratory, and 1.0% other sites. Among these, 60% were CA and 40% were nosocomial. Of antibiotics tested, only cotrimoxazole resistance was associated with nosocomial acquisition. The 3455 patients contributed 7003 person-years at risk. The incidence of CS-MRSA infection increased 6.2-fold from the first to the last half year. In multivariate analysis, independent predictors of CA-MRSA infection included HIV transmission by men who have sex with men or by injection drug use, CD4 count <50 cells/muL, log10 HIV plasma viral load, and absence of cotrimoxazole prophylaxis.


CONCLUSIONS
The incidence of initial CS-MRSA events increased more than 6-fold in a 4-year period. The associations between CA-MRSA infection and HIV severity indicators merit examination in other cohorts.
Mathews
Wm Christopher
WC
Department of Medicine, University of California, San Diego, Owen Clinic, UCSD Medical Center, San Diego, CA 92103, USA. cmathews@ucsd.edu
Caperna
Joseph C
JC
Barber
R Edward
RE
Torriani
Francesca J
FJ
Miller
Loren G
LG
May
Susanne
S
McCutchan
J Allen
JA
D000328:Adult; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D015994:Incidence; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000150:complications / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*