These letters and numbers come from the genomics database from where these frequencies came from. So they are part of a scientific taxonomy, or classification. If you want to know the specific meaning you're going to have to do some research on your own.
You can do a grade scan with Spooky Pulse or GenX on the preset found in the Presets tab under >DNA, >Bacteria, >Contact, Staphylococcus aureus (DNA) (C) - JW, and find the exact best staph frequency for you.
For more details, please check the link: