It appears that indeed climate change is allowing the bacteria to spread: https://www.scientificamerican.com/article/flesh-eating-bacteria-may-be-spreading-to-be... Apparently the offending bacteria is Vibrio vulnificus. According to Wikipedia, Necrotizing fasciitis is a condition that can be caused by a number of bacteria, one of which, one of the worst in fact, is Vibrio vulnificus. If Vibrio vulnificus is spreading due to global warming, this raises the question of what other pathogens will benefit from climate change.