A Mutation of RNA Polymerase β′ Subunit (RpoC) Converts Heterogeneously Vancomycin-Intermediate Staphylococcus aureus (hVISA) into “Slow VISA”

Vancomycin (VAN) Combinations with Β-Lactams (BLs) against Methicillin-Resistant Staphylococcus aureus (MRSA), Heterogeneous Intermediate-Level Resistance to Vancomycin (hVISA) and Vancomycin-Intermediate Staphylococcus aureus (VISA)

Daptomycin non-susceptibility in vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous-VISA (hVISA): implications for therapy after vancomycin treatment failure.

OBJECTIVES The aim of this study was to establish the relationship between reduced vancomycin and daptomycin susceptibility among Australasian vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous-VISA (hVISA) isolates from patients never exposed to daptomycin. METHODS Forty-seven stored clinical isolates of hVISA/VISA collected before November 2008 from around Australia and ...

"Slow VISA," a novel phenotype of vancomycin resistance, found in vitro in heterogeneous vancomycin-intermediate Staphylococcus aureus strain Mu3.

Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) clinical strain Mu3 spontaneously generates VISA strains at an extremely high frequency (≥1×10(-6)). The generated VISA strains usually grow more slowly than does the parent hVISA strain, but they form colonies on vancomycin-containing agar plates before 48 h of incubation. However, we noticed a curious group of VISA strains, d...

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks.

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen ...

Generation of a vancomycin-intermediate Staphylococcus aureus (VISA) strain by two amino acid exchanges in VraS.

OBJECTIVES Staphylococcus aureus is a notorious bacterial pathogen and antibiotic-resistant isolates complicate current treatment strategies. We characterized S. aureus VC40, a laboratory mutant that shows full resistance to glycopeptides (vancomycin and teicoplanin MICs ≥32 mg/L) and daptomycin (MIC = 4 mg/L), to gain deeper insights into the underlying resistance mechanisms. METHODS Genomic...