Blood in kitten's stool

Hi, I have a female British Shorthair kitten, around 3 months old. She has been with us about 1 month.

The first week after we brought her back, we noticed that there was blood in her stools, which were also a bit watery, and we took her to the vet. The vet gave us deworming medicine, diarrhea medicine and also some anti-biotics for the stomach to take for 1 week. The anti-biotics seemed to work, because the blood was gone after a few days. My husband took her back for review and the vet gave us some probiotics. After feeding her the probiotics and a few days before her next review, she started having blood in the stools again. The vet told us to stop the probiotics and to give her the same anti-biotics, which we are doing so now.

I would also like to highlight that when we brought her back, we made the mistake of changing the brand of kitten food she was on, which we suspect may have cause blood in her stools. Now, we are slowly trying to introduce back the previous brand of kitten food while on the anti-biotics. Her latest poop today still had some blood.

Besides the blood in her stools, she seems to be in good health, she eats regularly (although after mixing in the previous brand of kitten food, she doesn't seem to like it and will only eat that as last resort) and is active. 

But we are still concerned because we still don't know the cause of the bloody stools and seems alarming as none of our friends with cats have experienced this before. We intend to seek a second opinion from another vet. 

Would anybody be able to advise what can cause bloody stools? Is her diet the main problem? We are really quite worried about her condition.

I would also like to add that she has not had her second vaccination, which was supposed to have been done on 4 Dec. The vet did not recommend that we get it done since she was still not well.

De-worm her again. It can take 2-3 treatments to completely clear their system of worms. And worms can cause bloody stools.

Keep her on the pro-botics till everything settles down too.

Did your vet do a fecal? There are a few things like Giardia and cocoidia that require specialize treatment to cure.  I hate fecals because 90% of the time they come back negative but it's worth doing to see if anything does come back positive.

If a fecal hasn't been done, it should be, but request that the specimen be sent to an outside lab and "tested for everything". The in-house tests don't cover all the possibilities. Specific antibiotics can then be prescribed based on the lab findings.

Reikitty, I didn't think that worms would cause blood in stools but we will consider doing this again. The vet we went to did a fecal smear using a specimen that we kept in the fridge at around 6am (we went to the vet at around 2.30pm). However she said that there was too much bacteria and basically the specimen wasn't accurate. 

Jcat, we are going to try another vet. I felt that the first vet wasn't competent. We did try doing a fecal smear with poop a few hours old but kept in the fridge but she said there was too much bacteria and the results wouldn't be accurate. 

Usually worms = runny poo but they can cause bloody poo. The nice thing about de-worming is you can't hurt a cat by properly de-worming them even if they don't have worms so it's worth a shot.

And yah, if you feel your vet was incompetent  I'd totally change vets too, its best to find a vet you like and makes you feel like your cat is getting the best care.