Intensive negativistic personality issues from a client.

Need a reference but how to navigate it??
Situation: Care recipients Dr’s knew I was transitioning last minute into full time caregiving and felt they needed to discuss with me the care recipients behavior, and how it might negatively affect me. This care recipient refused to plan ahead knowing she was very ill and I was her only person,(for the last 5 years).
This person I help told doctors that they could share things with me… and said they could share things with me in front of three nurses and her present as the consenting Director of her own care.
So, Dr’s pulled me aside and went through a list of her “observable behaviors” in the phys rehab hospitals,and I’m glad they did. (person wasn’t diagnosed because they refused a psych eval),
I have never dealt with anyone that was called to have “negativistic personality“ traits.
But her behavior is still affecting me hugely by putting me at risk for extensive drug resistant bacterial infections. Many, many extensive drug resistant bacteria. She continues lying and does all kinds of covert obstructions against cleanliness practices, good personal hygiene, and universal precautions.
Now, after two years of direct hands on care and seven overall years of patient and thoughtful service, I have three of these XDR bacterial infections and she’s the only person I help.
I had to insist to my Drs that my bacterial tests were DNA tests. As a lot of these are such a rare isolates, (that she carries doesn’t treat and exposes us to knowingly),
that they don’t show up on regular augers or growth mediums the way the regular species of these bacteria do. DNA testing for bacterial infections is really the only way now to know conclusively. And I had to pay for it.
It’s conclusive.
She’s known about her bacteria for years and has denied it to each of the caregivers,( there’s no crossover between us), but we are all finding out and we recently patiently, but honestly, confronted the situation and her, all together recently.
Where we’re at now:
she’s refused to do most anything the doctors say, but tells everyone she will, but we still have to bed bath and and bladder flush.
She seems to have people that are sycophantic around her.
And people that only want to cosign really negativistic personality type behaviors(again not diagnosing just going on with all the doctors and nurses have told me), and I’m at a loss after seven years.
My universal precautions are flawless,
we have PPE and I’m very trained and wise. I insist on Lysol IC and safe sanitation practices, but her lack of self care is horrendous and we offer to do everything.
It’s been years, but her procrastination about getting almost all things done to make it safer for all of us by her bodily care are things she says constantly she’ll do and refuses to do,
says she’ll plan a bed bath with the next shift and never does,
told by her doctors bed bathing is not going to work because her XDR’s are all over her skin/urine and body fluids, and she needs to shower.
but keeps making barriers to it even though the water temperature is safe, all safety precautions have been put in place, we would do all the work, she has tons, and tons of money to buy any equipment that she needs, and she has all the support from us.
She lies about most everything, and is the most well is well provisioned for care recipient I’ve ever seen.
Lies about emptying her cath bag into the home health aids toilet, dumping her cath bag with(with diagnosed XDR bacteria, some of which get real serious real quick). Urine saturated hands, she goes around the house and touches everything. Years of this. I’m finally putting my proverbial foot down and have laid out the contamination control and infectious disease control details down,(yet again), am ready to walk. Thank you for reading:how might I ask passively-aggressive,(negavisticic), care recipient for a letter of reference after 7 years of caring and professional service.