infecto

Anyone have any experience with it? I was thinking about getting a puppy but I already have two house cats. One of the cats is scared of everything and anything not matter what it is and the other one has a real bitchy personality, doesn't like anyone including myself half the time lol. Ill be petting her and then stop and put my hand next to her or something and she will bite me. I have a feeling she will be very aggressive to a new animal. Any opinions?