Computerized antibiogram for methicillin-resistant Staphylococcus aureus in chest surgery.

BACKGROUND: An increasing number of cases of postoperative morbidity involving methicillin-resistant Staphylococcus aureus have been reported in thoracic surgery. To prevent its outbreak, cluster analysis using a personal computer was employed. METHODS: A total of 120 patients undergoing operations on the lung and mediastinum were included into this study. Materials were isolates of methicillin-resistant Staphylococcus aureus newly recovered from across the hospital. The cluster analysis used antimicrobial susceptibility in 12 drugs, which were categorically valued to produce Euclidean distance to form clusters of similarity. RESULTS: Six of the 120 patients were found to be positive for the microbe before or after thoracotomy. A total of two patients (1.7%) became symptomatic postoperatively, i.e., one of four preoperatively-positive patients and one of two postoperatively-positive cases. The analysis suggested that preoperative patients shared the strains in the same non-surgical ward. DISCUSSION: A computerized antibiogram does not always strictly type Staphylococcal strains but has advantages in typing with ease and at decreased cost. The current analysis suggested that patient harboring the strains migrated across wards. CONCLUSION: Computerized antibiograms for Staphylococcal strains may assist to prevent an outbreak of their infection in chest surgery.