POSTOPERATIVE MEDIASTINITIS DUE TO METHIC ILLIN-RESISTANT STAPHYLOCOCCUS-EPIDERMIDIS WITH LOW SUSCEPTIBILITY TO VANCOMYCIN

Background, -Vancomycin is the drug of choice for methicillin-resistan t Staphylococcus. Antibiotherapy failure is rarely clinically related to Staphylococcus, with vancomycin low susceptibility. Case report, -A surgical cure of an aortic stenosis in a neonate was complicated by a Staphylococcus mediastinitis. After inhibition of antibiotherapy with vancomycin and rifampin and surgical debridement, there was a rapid i mprovement. Few days later, failure of therapy was obvious. Despite co ntinuous infusion of vancomycin, with a serum level of 29 mg/L, blood cultures were positive again To Staphylococcus. There,vas no endocardi tis or inadequate surgical drainage. Susceptibility of the Staphylococ cus was tested, looking Soi a tolerant strain. The vancomycin minimum bactericidal concentration was 30 mg/L (above usual value 2 to 8 mg/L) , while the minimum inhibitory concentration was 3.75 mg/L. A higher d osage of vancomycin associated with fusidic acid was rapidly efficient , and total recovery was achieved. Conclusion, -In case of failure of vancomycin therapy, despite correct serum levels, the susceptibility o f the Staphylococcus strain has to be determined. A low susceptibility strain prescribes more prolonged combination of two antibiotics.