Low-level methicillin resistance in strains of Staphylococcus aureus

Prevalence of Vancomycin Resistance in Methicillin-Resistant Staphylococcus Aureus

Background & Aims: Staphylococcus aureus is one of the most common pathogens in nosocomial infections. Vancomycin is the most important therapeutic drug of choice for treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains. Therefore, vancomycin-resistant Staphylococcus aureus (VRSA) or vancomycin-intermediate Staphylococcus aureus (VISA) strains are warning...

Vancomycin Resistance in Staphylococcus aureus Strains

Phenotypic Changes of Oxacillin Resistance in Methicillin-resistant Staphylococcus aureus Strains by Successive Passaging

Background and purpose: Rotational use of antibiotics can decrease antibiotic resistance in Staphylococcus aureus strains. The present study aimed to evaluate the alteration of oxacillin resistance in methicillin-resistant Staphylococcus aureus (MRSA) strain carrying SCCmec III cassette in long-term evolutionary experiments in an antibiotic-free medium. Materials and methods: In a cross-sectio...

Expression of methicillin resistance in heterogeneous strains of Staphylococcus aureus.

The phenotypic expression of methicillin resistance was studied in a number of clinical isolates and laboratory strains of Staphylococcus aureus. The methicillin-resistant S. aureus strains could be divided into three classes, homogeneous, heterogeneous, and thermosensitive heterogeneous methicillin-resistant S. aureus, on the basis of their plating efficiencies at 30 or 37 degrees C on methici...

Examination of methicillin-resistant and methicillin-susceptible Staphylococcus aureus mutants with low-level fluoroquinolone resistance.

For Staphylococcus aureus, stepwise mutations result in high-level quinolone resistance. Methicillin-resistant and -susceptible quinolone-resistant, first-step mutants generated in vitro were obtained and found to be no different than those recovered from murine abscesses. Approximately 10% of all first-step mutants were resistant to ethidium bromide, and selected strains had mutations that map...