Vancomycin Heteroresistance in Methicillin-resistantStaphylococcus aureus, Taiwan

Vancomycin Heteroresistance in Methicillinresistant Staphylococcus aureus, TaiwanTo the Editor: In 1997, Hiramatsu and colleagues reported the first clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) showing reduced susceptibility to vancomycin (1).Soon thereafter, vancomycin-intermediate S. aureus (VISA) or heteroresistant VISA was reported to have disseminated in Japanese hospitals (2).In Taiwan, a survey of >5,000 clinical isolates of S. aureus at one tertiary medical center from 1999 to 2001 showed negative results for VISA or vancomycinresistant S. aureus (VRSA) (3,4).We report the first two isolations of heteroresistant VISA in Taiwan.In June, 2000, an 89-year-old man (patient A) with a history of cerebrovascular accident underwent ileal resection for ischemic bowel disease, and primary MRSA bacteremia developed during the hospitalization.Vancomycin was given for 14 days, and his fever rapidly abated.In October 2000, a Port-A-Cath (Smiths Industries Medical Systems, Deltec, Inc., St. Paul, MN) was inserted in the left subclavian vein.On June 14, 2001, he had another blood isolate of MRSA during an episode of Enterococcus faecalis bacteremia.Fever resolved after 4 days of intravenous vancomycin treatment (1 g every 12 h), and vancomycin treatment was continued for 21 days.Subsequent culture of blood drawn from the Port-A-Cath and peripheral veins on June 29 and July 6, 2001, did not yield any organism.