Methicillin-resistant Staphylococcus aureus clinical strain with reduced vancomycin susceptibility

Abstract

(MRSA) with reduced suscept-ibility to vancomycin (MIC 8 mg/L). The strain was isolated from a surgical wound infection which was refrac -tory to vancomycin therapy.In May 1996, a 4 month-old male infant underwent heartsurgery for pulmonary atresia. Two weeks followingsurgery, the infant became febrile and developed a purulent discharge from the sternal surgical incision site;culture of the purulent material yielded MRSA. The patientwas treated with vancomycin (45 mg/kg daily) for 29 days,but fever and discharge of pus continued, and the C-reactive protein (CRP) remained elevated (40 mg/L). Thetreatment was changed to a combination of vancomycin andarbekacin (an aminoglycoside approved for MRSA infec-tion in Japan). After 12 days of this regimen, the purulentdischarge subsided, the wound began to heal, and the CRPdeclined from 40 to 9 mg/L. The antimicrobial therapy wasdiscontinued. However, 12 days later the surgical siteappeared inflamed with the development of a subcutaneousabscess accompanied by a sudden onset of fever and a raised CRP level of 35 mg/L. Therapy was resumed with the com -bination of arbekacin and ampicillin/sulbactam which hasbeen shown to have synergic activity against MRSA.