I would not worry about finding out the specific type of bacteria, it doesn't really matter, they all react to the same antibiotics, anyway. Enrotril is enrofloxacin which is the generic name (and ingredient) for Baytril, the most commonly prescribed wide-spectrum antiobiotic for birds so you are good. It's very effective and, although it can have side effects like nausea, I've never had a single problem with it and have used it a lot (as a matter of fact, I have a very old amazon on it right now).
I would not use betadine for the cage, I would use a 10% solution of what we call Clorox here in the States which is regular clothing bleach (sodium hypochlorite). It's cheap and the most effective disinfectant (the one recommended in the USDA disinfection protocol for avian diseases). Just do it in another room (you don't want him to breathe in the fumes), rinse thoroughly and allow to air dry (and, if you can dry it out in the sun, better still).
Now, yes, the avian vet is right and he is not really been cagey, bacterial infections can come from anywhere so it cannot really be traced back to the breeder BUT birds only get them when their immune system is depressed (that's why he mentioned stress which does mess up the immune system something terrible). A healthy, well raised, well-fed baby bird should not get a bacterial infection just because he was sold. But you already figured out that these people are not as caring or as careful as they should be so no news there, right?
Warmth is essential and that means 27 to 30 Celsius. I like heating pads put at the bottom of the cage covered by some type of cloth (like a kitchen or bath towel, for example) and another sort of material (I also use towels for this) covering the entire cage except the front of it (which you need to leave open for light). This makes the heat concentrate inside the cage but there is still fresh air coming in.
I usually give them one week worth of antibiotics and rest for one day before I start again with it to continue the treatment, and, on this day of rest, I give them a large dose of probiotics (I use human ones, the ones that have the most number of strains and with, at least, 1 billion colony forming units) and, when I am done with the antibiotic, I give them the probiotics five days in a row. This is because, although there is always bad bacteria, it is usually kept in check by the good bacteria so, when you don't have enough good bacteria, the bad bacteria proliferates thereby causing the infections. But, when you give antibiotics, you are killing both good and bad bacteria as the medicine does not discriminate between good and bad so, in order to replenish the intestinal flora and to prevent a relapse, a good dosing with probiotics is essential.
But OUCH! on the price of the PBFD test! I did the conversion and that's over US$250! That's HUGELY more expensive than what we pay here in the States and you can have it done yourself with internet labs for even less (see here:http://www.avianbiotech.com/Pricing.htm). This is the lab I use for testing and DNAing the new birds. I take the bird to the vet and ask them to take a bit more blood (they take for the CBC and the avian chem panel so they don't charge me extra for this) and put it in the vial (the company sends you a kit on the mail) and send it overnight to the lab and have them done the 'combination' test which is even cheaper.





