Control of methicillin-resistant Staphylococcus aureus bacteraemia in high-risk areas

In a 3,000-bed tertiary care hospital, 88 cases of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia were identified from 22,383 blood cultures (0.39%) submitted to the microbiology laboratory over a one-year period. Two high-risk areas were identified: the paediatric oncology unit, in which 12 cases of MRSA bacteraemia were identified from 924 blood cultures (1.3%), and the intensive care unit (ICU), in which 14 cases of MRSA bacteraemia were identified from 1,391 blood cultures (1.0%). In a one-year targeted intervention programme in which staff and patients were screened for MRSA carriage, patient carriers isolated, and mupirocin and chlorhexidine treatment administered, the number of MRSA bacteraemia cases decreased in these areas to 0 and 4, respectively (p = 0.000123 and 0.016), while the incidence of MRSA bacteraemia in non-targeted areas increased from 62 of 20,068 blood cultures (0.3%) to 82 of 18,784 blood cultures (0.44%) (p = 0.047). In the year post intervention the incidence of MRSA bacteraemia increased to 3 of 815 cultures (0.37%) in the paediatric oncology unit, 10 of 1,934 cultures (0.5%) in the ICU, and 112 of 18,977 cultures (0.59%) in the rest of the hospital (p = 0.00004 versus preintervention period). This study demonstrates the efficacy of targeted MRSA control measures in a hospital in which MRSA is endemic.