Risk factors for clinical infection in patients colonized with methicillin resistant Staphylococcus aureus (MRSA)

To identify the risk factors involved in development of infection in individuals colonized with Methicillin-resistant Staphylococcus aureus (MRSA) among intensive care unit (ICU) patients.

A total of 1431 patients were admitted in ICU of which 63 grew MRSA during January 1998 to December 1999. Patients who developed infection with MRSA in less than 48 hours of their admission to ICU were excluded. Medical records of all patients who grew MRSA were reviewed and 57 patients were identified for inclusion in the study. Thirty-seven of these had features of infection with MRSA and were selected as cases and 20 were identified as asymptomatic colonizers and labeled as controls. Risk factors like age of the patient, duration of ICU stay, gender, co-morbidity, presence and duration of central lines, number of arterial-punctures and number and duration of intubations were compared between cases and controls.

Cases were found to be significantly older (52.8 +/- 15.1) than controls (34.9 +/- 21.2). Other identified risk factors were diabetes mellitus (p = 0.001) and the first 15 days of central line placement (p = 0.025). Although chronic liver disease and hypertension could not be identified as significant risk factors, they clearly showed association. Other risk factors were not significantly different from controls.

It is suggested that greater care is required for the elderly, diabetic patients with a central venous line in place especially during the first fifteen days of its introduction.