VISA-type vancomycin resistant strain. Staphylococcus aureus subsp. aureus JH9

Staphylococcus aureus subsp. aureus strain JH9. A series of isogenic methicillin-resistant (MRSA) strains were isolated from a patient undergoing vancomycin treatment. The chronologically earliest strain (JH1) was vancomycin sensitive, while the latest strain (JH9) exhibited increased vancomycin resistance (VISA-type vancomycin resistance). Comparison of these two strains will enable understanding of the evolutionary events that occur under the selective pressure of the presence of antibiotics as well as help explain the genetic basis for vancomycin resistance.