Risk factors for acquisition of meticillin-resistant Staphylococcus aureus and clonal spread of the isolates in a medical intensive care unit

Abstract number: P1768

Alp E., Yerer M., Esel D., Metan G., Doganay M.

Objectives: Meticillin-resistant Staphylococcus aureus (MRSA) is still commonest pathogen in hospital-acquired infections with high morbidity and mortality.MRSA colonisation usually precedes infection and dissemination of microorganism. The aim of this study was to determine risk factors for the colonisation and infection with MRSA in medical intensive care unit (MICU) and show the genetic relatedness of the strains.

Methods: This study was conducted prospectively between 1 December 2004 and 31 January 2006 in MICU. Patients (>16 years) admitted to the MICU were screened for MRSA on admission (in the first 48 hours), weekly during prolonged ICU stay, and at ICU discharge using anterior nares, axilla and groin swabs. Patients, stayed shorter than 48 hours and admitted with MRSA colonisation or infection, were not evaluated for the risk factors. Also, healthcare-workers (HCWs), close contact with these patients, were screened for nasal colonisation at the beginning and end of their ward rotation. Patient data was collected for risk factors evaluation. Genotyping analysis was performed by pulsed-field gel electrophoresis (PFGE) at the Infectious Disease Laboratory of Hacettepe University.

Results: During the study period, 259 patients were evaluated for the risk factors of MRSA acquisition. The colonisation rate was 18.5%. The mean time for MRSA acquisition was 12.7 days (range 4 to 66 days) after admission. The anterior nares were the most frequent site (87.5%) of MRSA colonisation. MRSA infection occurred in 15 (31%) of 48 colonised patients. In four patients, MRSA infection developed unless colonisation was determined. Nasal carriage of MRSA wasn't detected in HCWs during study period. In multiple logistic regression analysis, only length of stay in MICU and mechanical ventilation were the significant risk factors for colonisation. On the other hand, MRSA colonisation and tracheostomy were the significant risk factors for infection. In genotyping analysis, four clones (clone A, B, C, D) were determined in colonised patients on admission and also patients colonised in MICU had same clones (clone A, B, C). Moreover 57% of these clones were clone B.

Conclusion: This study shows the clonal spread of MRSA in an ICU and supports the results of previously published reports. Despite the efforts to improve hand hygiene (reminder posters, bedside alcohol-based products, staff education), the problem emerges because of understaffing and high workload in a developing country.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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