To the Editor: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most frequently isolated bacterial pathogens in nosocomial infections. MRSA strains recently have emerged that show reduced susceptibility to vancomycin, including vancomycin-resistant S aureus (VRSA), vancomycin-intermediate S aureus (VISA), and S aureus heterogeneously resistant to vancomycin (heterogeneously resi...

BACKGROUND AND OBJECTIVES During a community methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization study, an MRSA strain with vancomycin hetero-resistance (h-VISA) was isolated from a five year-old girl with tetralogy of Fallot without previous exposure to vancomycin. An extended nasal colonization study was performed on all her close relatives. RESULTS Only the patient and he...

The peptidoglycan compositions of vancomycin-resistant Staphylococcus aureus (VRSA) strain Mu50 (MIC 8 mg/L) and hetero-VRSA strain Mu3 (MIC 3 mg/L) were compared in order to understand the mechanism of vancomycin resistance. As compared with Mu3, the cell wall of Mu50 had increased amounts of glutamine-non-amidated muropeptides and decreased cross-linking of peptidoglycan with a greatly decrea...

The emergence of drug-resistant pathogens such as staphylococci and enterococci in the hospital setting has long being recognized as a serious clinical problem. Staphylococcus aureus is the causative agent of many nosocomial infections from minor skin abscesses to serious, potentially life threatening diseases such as bone and soft tissue intra-surgical infections, sepsis and invasive endocardi...

We have previously reported methicillin-resistant Staphylococcus aureus clinical strains, Mu50 and Mu3, representing two categories of vancomycin resistance: Mu50 representing vancomycin-resistant S. aureus (VRSA) with MICs > or = 8 mg/L, and Mu3 representing hetero-VRSA with MICs < or = 4 mg/L using standard MIC determination methods. The mechanisms of vancomycin resistance in these strains we...

Methicillin-resistant Staphylococcus aureus (MRSA) is an important opportunistic pathogen that causes both healthcare- and community-acquired infections. An increase in the incidence of these infections may lead to a substantial change in the rate of vancomycin usage. Incidence of reduced susceptibility to vancomycin has been increasing worldwide for the last few years, conferring different lev...