Old newts and diet changes

Hi everyone,
I posted a note just a couple of days ago asking for help for my T. gran Izzie (see my post below 'How to distinguish bloat from less harmful conditions'). He looked so miserable last night so I took him to a vet who specializes in exotics. They did a blood count and found his white blood cells, neutrophils as well as eosinophils in increased numbers, indicators for a bacterial as well as parasitic infection. Izzie is 12 years old and had been on a diet of frozen bloodworms until I adopted him. When I got a second T. gran, Moe, she was on a diet of blackworms. I started feeding both both of them blackworms. The vet said that newts have naturally a variety of bacteria in their GI tract, but that the rich diet might have triggered them to proliferate. He gave him his first dose of broad-spectrum antibiotics and anti parasite medication. He will be on it for 10 days. I will attempt tonight to administer the meds myself. I thought I was doing something good for Izzie, feeding him live nutritious worms, but I guess this was a hard lesson to learn and I would like to advice anyone who adopts and older newt not to change the diet. It can do a lot more harm than good. He started shedding almost immediately after leaving the vets office, probably triggered by the stress of being handled. The vet said he has a chance of survival, but that it is more difficult for older newts to recover from an infection. Izzie didn't look much better this morning, but I hope that in a couple of days the meds will kick in. It does seem that the swelling of his abdomen decreased a little. Oh, also, the black lines on the side of this body I was concerned about are protruding veins and the vet said that this will get better as he fights the infection. The arteries on his ventral side are also a lot more visible due to the infection. I will keep you guys posted on his progress.

Often with a steady diet the flora of the intestional tract will become acclimated to the diet (this is often seen in herbivores that are subjected to a sudden change in the diet (usually due to a surge in sugars)) but I have not heard of this before in carnivorous herps....
But as I understand it, the damage is due to the rate at which the diet is changed not necessarily from changing the diet in the first place.

I guess another possibility would be that he could have picked up parasites from Moe.

I tried feeding Izzie blood worms tonight, but he refused to eat anything. It is the second day that he hasn't eaten. I read that newts can go without food for a couple of days, but when should I start to worry? And is there anything I can do to get him to eat?

All you can do is keep trying. Often, sick newts won't eat. He can actually go for several weeks without food, but it would be better if he ate.

Thank you Jennifer, I contacted the vet as well, and he said I should give it another day. I was able to give him is meds yesterday although he really did not like the idea of me trying to get the syringe into his mouth. It did seem that he swallowed the whole dose.