How should local clinical laboratories save presumptive VISA or VRSA isolates?
It is best to freeze isolates at -60°C or lower in standard stock culture medium, such as a broth containing 15% glycerol, or in defibrinated sheep blood. However, if a laboratory cannot do this, the isolate should be subcultured to a non-selective agar slant (e.g., trypticase soy agar) and incubated overnight at 35°C. The following day, the caps should be tightened and the slants stored at 2-8°C. Repeated subcultures should be kept to a minimum prior to storage.
