Factors influencing the success or failure of meticillin-resistant Staphylococcus aureus decolonisation protocols

Abstract number: P1770

Gilpin D.F., Small S., Kearney P., Gardiner A., Tunney M.

Objectives: Meticillin resistant Staphylococcus aureus (MRSA) is a leading cause of nosocomial infection. Colonisation, often the precursor to infection, can prove difficult to eradicate with many patients remaining MRSA positive despite repeated attempts at decolonisation. This study attempts to analyse factors, which may influence the success or failure of MRSA decolonisation protocols currently in use in the Northern Health and Social Care Trust in Northern Ireland.

Methods: Restriction enzyme digestion (SmaI), followed by PFGE was used to identify strain differences in isolates from successfully and unsuccessfully decolonised patients. Successfully decolonised patients are currently being re-screened at 6 and 12 months. If positive, PFGE will be used to determine whether the patient has been persistently colonised with the same strain, or has been re-colonised with a new strain. Determination of the susceptibilities of the isolates to mupirocin was determined using E-test™.

Results: To date, 296 patients have been recruited to the study, of which 127 have been removed due to death, a worsening of their underlying medical condition or non-compliance. Sixty patients have failed decolonisation. In almost all patients examined, identical MRSA isolates were observed before and after decolonisation. However, in a few cases, a different MRSA strain was isolated before and after decolonisation, suggesting that the patient may have been re-colonised with a second MRSA strain. Eighty-one patients were successfully decolonised, of which 31 have been re-screened at 6 or 12 months. Of these, ten patients were found to be MRSA positive, in some cases with a different strain. The susceptibilities of isolates from 42 patients, who failed decolonisation, to mupirocin were determined by E-test™. Fifteen patients (35.6%) were found to have MRSA isolates, which were considered resistant to mupirocin (MIC value >1024 mg/L). Patient medicals histories are currently also being examined

Conclusions: This study has shown that current decolonisation protocols can in many cases be successful, with a substantial proportion of patients remaining MRSA negative at 6 and 12 months post decolonisation. Failure of MRSA decolonisation protocols may be due to several patient factors (e.g. frequent contact with healthcare providers, movement between wards or failure to adequately carry out the decolonisation protocols) or due to the acquisition of mupirocin resistant MRSA.

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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