Random meticillin-resistant Staphylococcus aureus carrier surveillance at a district hospital and the impact of interventions to reduce endemic carriage

Colonisation with meticillin-resistant Staphylococcus aureus (MRSA) has previously been described as a risk factor for subsequent infection. MRSA colonisation reached endemic proportions in most healthcare institutions in the UK during the 1990s. Bacteraemia due to MRSA is associated with increased mortality and morbidity compared with meticillin-susceptible S. aureus and national targets have been set for reduction. We present our findings of regular random colonisation surveillance and systematic decolonisation of MRSA carriers over a five-year period with the aim of reducing the pool of carriers and number of MRSA bacteraemia cases. Interventions to reduce the rate of colonisation included assurance of decolonisation and follow up, targeting wards with the highest carriage rates using enhanced screening and education, and screening all admissions aged >65 years. There was a statistically significant reduction in the proportion of patients colonised from 14.6% to 7.0% (P < 0.001) and the total number of bacteraemia cases from 42 to 22 (P = 0.012) in the initial 24 months of surveillance compared to the most recent 24 months. Regular surveillance of MRSA carriage is useful for monitoring the effects of control measures on MRSA carriage among inpatients. Interventions to reduce carriage are able to reduce the pool of MRSA carriers, thereby reducing cases of bacteraemia.