Updated (by Mark): Don't panic. Fenway Community Health has an informative web site about this alert and how to reduce your risk here.
This is frightening.
The New York Times is reporting that a new, highly drug-resistant strain of bacteria is spreading rapidly among gay communities in San Francisco and Boston.
According to researchers, this new strain of the "flesh-eating" MRSA bacteria "seemed to be spread most easily through anal intercourse but also through casual skin-to-skin contact and touching contaminated surfaces."