Methicillin-resistant Staphylococcus aureus bacteraemia in Hong Kong.

In the first 22 months of operation at the Prince of Wales Hospital, 26 (46%) of 56 hospital-acquired Staphylococcus aureus bacteraemias were due to methicillin-resistant organisms (MRSA). There were 10 plasmid profiles amongst 24 of the MRSA strains analysed. MRSA bacteraemias were first seen in the hospital 1 year after opening when the isolation rate of MRSA from all sites had risen to about 1% of patient admissions. During the last 3 months of the study period, 17 out of 18 S. aureus bacteraemias were due to methicillin-resistant strains. Patients with MRSA bacteraemia were significantly more likely than those with methicillin-sensitive S. aureus bacteraemia to have had a severe underlying disease, a poor clinical prognosis, prolonged hospitalization, and prior antimicrobial therapy, especially with aminoglycosides. They also had a significantly longer hospital stay after infection, a significantly higher cost of antimicrobial therapy and a higher mortality rate. The lower mortality rate in MRSA patients treated with vancomycin (18%) compared with those treated with other antimicrobials (40%) confirms that, at present, vancomycin is the treatment of choice for invasive MRSA infections.