Is an increase of MRSA in Oslo, Norway, associated with changed infection control policy?

Objectives: The objective was to describe the prevalence of MRSA in Oslo, Norway, before and after introduction of a new National MRSA Control Guideline. Methods: From 1993 to 2006, we prospectively collected clinical and microbiological data on all MRSA cases in Oslo, Norway. Two MRSA guidelines; a strict Ulleval Standard MRSA Guideline and a less strict National MRSA Control Guideline were compared. Results: During 1993-2006, 358 MRSA cases were registered in Oslo; 43.9% detected in Ulleval University Hospital, 21.2% in nursing homes, and 18.7% in primary healthcare. One out of three (30.4%) were import-associated, and one out of ten (11.2%) were healthcare personnel. From 2004 on, a new National MRSA Control Guideline was introduced in primary healthcare, served by the community infection control. From 2004 on, there was a 4-6-fold increase of MRSA in primary healthcare (p = 0.038) and nursing homes (p = 0.005). Increase of MRSA cases at Ulleval (p < 0.001) was import-associated or from outbreaks in primary healthcare. There was no increase of internal spread in the hospital. Conclusion: These data indicate that perhaps a less strict national MRSA infection control guideline in Norway may be associated with the 4-6-fold increase of MRSA cases in the community after 2003. (c) 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved.