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Open Access Research article

Community-associated Methicillin-resistant Staphylococcus aureus Bacteremia and Endocarditis among HIV Patients: A cohort study

Jon P Furuno15, Jennifer K Johnson2, Marin L Schweizer3, Anayochukwu Uche4, Oscar C Stine5, Simone M Shurland56 and Graeme N Forrest7*

Author Affiliations

1 Department of Pharmacy Practice, Oregon State University/Oregon Health and Sciences College of Pharmacy, Portland, OR, USA

2 Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA

3 Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA

4 Oro Valley Hospital, Oro Valley, AZ, USA

5 Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA

6 Food and Drug Administration, Silver Spring, MD, USA

7 Division of Infectious Diseases, Portland VA Medical Center and Oregon Health Science University, Portland, OR, USA

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BMC Infectious Diseases 2011, 11:298  doi:10.1186/1471-2334-11-298

Published: 31 October 2011

Abstract

Background

HIV patients are at increased risk of development of infections and infection-associated poor health outcomes. We aimed to 1) assess the prevalence of USA300 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among HIV-infected patients with S. aureus bloodstream infections and. 2) determine risk factors for infective endocarditis and in-hospital mortality among patients in this population.

Methods

All adult HIV-infected patients with documented S. aureus bacteremia admitted to the University of Maryland Medical Center between January 1, 2003 and December 31, 2005 were included. CA-MRSA was defined as a USA300 MRSA isolate with the MBQBLO spa-type motif and positive for both the arginine catabolic mobile element and Panton-Valentin Leukocidin. Risk factors for S. aureus-associated infective endocarditis and mortality were determined using logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). Potential risk factors included demographic variables, comorbid illnesses, and intravenous drug use.

Results

Among 131 episodes of S. aureus bacteremia, 85 (66%) were MRSA of which 47 (54%) were CA-MRSA. Sixty-three patients (48%) developed endocarditis and 10 patients (8%) died in the hospital on the index admission Patients with CA-MRSA were significantly more likely to develop endocarditis (OR = 2.73, 95% CI = 1.30, 5.71). No other variables including comorbid conditions, current receipt of antiretroviral therapy, pre-culture severity of illness, or CD4 count were significantly associated with endocarditis and none were associated with in-hospital mortality.

Conclusions

CA-MRSA was significantly associated with an increased incidence of endocarditis in this cohort of HIV patients with MRSA bacteremia. In populations such as these, in which the prevalence of intravenous drug use and probability of endocarditis are both high, efforts must be made for early detection, which may improve treatment outcomes.