Just from the pictures I would tend to think its some kind of injury rather than an infection. I saw some pictures of a cat that had gotten glue all over it and the bare spots were specific to where the glue was. There are all kinds of things that can cause chemical like burns, strong bleach is one that comes to mind. Diesel fuel can cause hair loss also. I have seen a horse that had it spilled/sloshed on it and it lost patches of hair in those areas. Infections are usually very splotchy whereas damage to an entire area is usually from an agent of some kind. I don't know if gasoline can cause that reaction in cats but even that is a possibility. It's likely going to need some kind of ointment to help the raw skin to heal up. Another thought/ possibility, hot oil can do that and maybe scalding water.
So this is a little hard to look at, but thank you google --- hot water scalding of cats---
hot water scalding in cat - Google Search
So this is a little hard to look at, but thank you google --- hot water scalding of cats---
hot water scalding in cat - Google Search