BACKGROUND: This study was conducted to investigate whether the preoperative nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) was a risk factor for surgical site infections and nosocomial infections in open heart surgery patients. METHODS: From June 10, 2002 to October 30, 2002, data were collected by prospective surveillance carried out by infection control nurses. Nasal swabs were taken from patients (N= 106) on the day before surgery. The swabs were incubated in staphylococcal broth for 24 hours, and then it was incubated on mannitol salt agar for 24 hours. Muller-Hinton agar supplemented with oxacillin (6 microgram/mL) was used to identify MRSA. RESULTS: Among the study patients (N=106), four(4/106, 3.8%) were identified as MRSA carriers and nine (9/103 , 8.7%) developed nosocomial infections, including three patients (3/103 , 2.9%) who had postoperative mediastinitis Preoperative nasal carriage of MRSA was not associated with nosocomial infections nor surgical site infections (P>0.05). However, the length of hospital stay prior to nasal swab or surgery was found to be associated with MRSA carriage (OR=1.108, 95%CI: 1.026-1.197) or nosocomial infections (OR=1.087, 95%CI: 1.017-1.161). Additionally, the patients with nosocomial infections were more likely than those without to stay in the hospital for a longer period after surgery (P<0.00l). CONCLUSION: Preoperative nasal carriage of MRSA by the patient was not identified as a risk factor for surgical site infection and nosocomial infections in open heart surgery.
Agar ; Cross Infection* ; Humans ; Infection Control ; Length of Stay ; Mannitol ; Mediastinitis ; Methicillin Resistance* ; Methicillin-Resistant Staphylococcus aureus* ; Oxacillin ; Prospective Studies ; Risk Factors ; Thoracic Surgery*