Pseudomonas in my cat's sinus - looking for a natural cure - anitibiotics are not working

I have a sweet small cat that had an ear polyp removed surgically. After that was done, she developed a bloody nose and congestion with mucous/blood. All the vets at the hospital said she must have a tumor or something because nothing was helping - including all sorts of antibiotics.

So after almost 8 months of trying many natural treatments, including colloidal silver, ACV, homeopathic remedies, I had endoscopic surgery to remove what the specialist thought, as I thought was another polyp.

After she went through the endoscope - they flushed her sinuses and found no polyp, no tumor but an area was inflamed. After getting back the lab results from a biopsy, we found she has pseudomonas. The specialist has her on a particular antibiotic called marbofloxacin. She has been on this treatment for nearly 3 weeks now and is no better!

I've studied this nasty pseudomonas during this time, and it is resistant to antibiotics, so it stirs up the bacteria and can make it worse! So, now I am trying to discover if anyone in the naturopathic world has an answer for this resistant bacteria.

I found one doctor in New Zealand who says that Grapefruit Seed extract and a full spectrum product he uses to kill Candidas will bring the pseudomonas under control. She has a bloody nose all the time, sometimes he seems to be getting better and then it flairs its ugly head.

She is on a home prepared diet that is from another holistic Doctor named Dr Pitcairn, who has many home prepared meals recipes for both dogs and cats with afflictions and non afflictions. She has been on the allergy diet for a long time and she looks beautiful - all the vets say the same. She has no other issue but the pseudomonas infection (which probably came from infected instruments at the vet hospital).

Are there any other cures anyone has found for their dogs or cats with this horrible stubborn affliction? I am determined to find a cure for this. Also the Dr from New Zealand, Dr Eric Bakker claims his remedy works. Also getting the gut in order with probiotics -

I share these things, but have yet to use them to see if there is improvements or cures. Anyone else found these remedies working?