Methicillin-resistant Staphylococcus aureus preventing strategy in cardiac surgery.

OBJECTIVES: The aim of this survey was to elucidate the efficacy of methicillin-resistant Staphylococcus aureus (MRSA) preventing strategy in our institution by investigating the incidence and evaluating the morbidity and mortality associated with this multi-resistant virulent organism.

METHODS: A prospective observational cohort among patients submitted to cardiovascular surgical procedures was conducted from 1 January 1997 to 31 December 2005. Preventing strategy included active screening programs by nasal swabs for all patients admitted from other hospitals or being at risk for developing infectious complications. Carriers or infected patients remained isolated and were treated promptly. Furthermore, all newly employed health care workers were screened for MRSA and carriers were treated with mupirocin until the eradication of the pathogen.

RESULTS: Throughout the 9-year study period 826 infectious complications were registered among 15,270 cardiac surgical patients. Total infection rate was 5.4%. MRSA was identified in 86 patients; 56 patients proved carriers and 30 infected. The MRSA associated infection rate was 0.2%. During this period of time mean ICU stay was 1.7 days and ICU mortality rate was 2.9%. MRSA infected patients presented a mean ICU stay of 46.5 days and a mortality rate of 30%. In ten patients, MRSA was detected in tracheal secretions, in four patients in swabs taken from donor site infection and in four patients from superficial sternal surgical wound. In ten patients the pathogen was isolated from cultures of the surgical site drainage and the diagnosis of post-sternotomy mediastinitis was confirmed. The remaining two patients were defined as having severe sepsis; MRSA was documented in central venous catheter tips and blood cultures.

CONCLUSIONS: The prompt determination, isolation and appropriate treatment of MRSA patients admitted from other institutions combined with the detection and elimination of carriers among new health care workers and patients at high risk of developing infectious complications prevented further spread of the pathogen.