Yup, those are the boys.
My wife was bit by one of our cats at the veterinarians. The vet cleaned and bandaged the bite. She went to work the next morning with a stiff hand. Four hours later she called me to come get her. Two hours later she was in the hospital, white as a sheet, with IV drips of industrial strength antibiotics, an arm the size of a leg, and a very, very worried hubby.
The villain turned out to be the bacteria whose fast deadly action was what caused Louis Pasteur to put together the idea of infections being caused by bacteria. Pre-WWII my wife would have died, or would have lost her arm.
This is scary stuff -- I have never seen an infection go so fast.