Research article

Role of previous hospitalization in clinically-significant MRSA infection among HIV-infected inpatients: results of a case-control study

Cecilia MJ Drapeau¹ , Claudio Angeletti² , Anna Festa³ and Nicola Petrosillo¹

¹  2^nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy

²  Epidemiology Department, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy

³  Microbiology Laboratory, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy

author email corresponding author email

BMC Infectious Diseases 2007, 7:36doi:10.1186/1471-2334-7-36

Published:	30 April 2007

Abstract

Background

HIV-infected subjects have high incidence rates of Staphylococcus aureus infections, with both methicillin-susceptible and methicillin-resistant (MRSA) strains. Possible explanations could include the high burden of colonization, the behavioral risk factors, and the frequent exposures to health care facilities of HIV-infected patients. The purpose of the study was to assess the risk factors for clinically- significant methicillin-resistant Staphylococcus aureus (CS-MRSA) infections in HIV-infected patients admitted to Infectious Diseases Units.

Methods

From January 1, 2002 to December 31, 2005, we conducted a retrospective case-control (1:2) study. We identified all the cases of CS-MRSA infections in HIV-infected patients admitted to the National Institute for Infectious Diseases (INMI) "Lazzaro Spallanzani" in the 4-year study period. A conditional logistic regression model was used to identify risk factors for CS-MRSA infection.

Results

We found 27 CS-MRSA infections, i.e. 0.9 CS-MRSA infections per 100 HIV-infected individuals cared for in our Institute. At multivariate analysis, independent predictors of CS-MRSA infection were cumulative hospital stay, invasive procedures in the previous year, and low CD4 cell count. Particularly, the risk for CS-MRSA increased by 14% per an increase of 5 days hospitalization in the previous year. Finally, we identified a low frequency of community-acquired MRSA infections (only 1 of 27; 3.7%) among HIV-infected patients.

Conclusion

Clinicians should be aware of the risk for CS-MRSA infection in the clinical management of HIV-infected patients, especially in those patients with a low CD4 cell count, longer previous hospital stay, and previous invasive procedures.