How can I get my mom to be more hygienic for her own safety without causing a huge argument?

She is 83 with dementia pretty bad at times. My mother has dementia since 2002. It is such a terrible disease for her, yet for me as well. Watching your parent disintegrate and disappear before your own eyes, yet trying to show her face to face it's not is torturing me inside to see. She is constantly getting UTI due to her refusal to bathe or shower. The doctors, caretaker, and myself try to explain this to her amd she seems almost to get ashamed and offended and begins a very hateful, truckers mouth, example- stating she should have aborted me, or I was a mistake. I know that is the illness talking, yes it still hurts. I am all she has because my brother and sister took the money dad left when he died in '02 and they want nothing to do with either. It's her and I and that's it. I made a promise to never put her in a home and will honor that always. I did that by my choice so, No, she hasn't taken away my life or ruined it. We get along amazingly, accept this darn sundowners. That's a tough one. I've learned to just let her say what she needs, hurtful or not and it does pass. You get one mother, she is mine and dementia or not I will do anything to be sure her last years are happy, and she does remember parts of things we've done. Her dementia is very advanced though. Any thoughts on what or how to get her more hygienically clean so her UTI doesnt become a monthly thing for her?