More than 100 different types of bacteria live inside a cat's mouth. Pasteurella are the most common bacteria in cats' mouths, according to Critter Chatter.
Since a cat's teeth are long and narrow, they can create deep puncture wounds where bacteria can thrive under the skin, explains Critter Chatter. Pasteurella can cause dangerous infections and permanent damage if left untreated. Pasteurella thrive in environments without oxygen, such as the area beneath the surface of the skin. First signs of pasteurellosis typically occur within a few hours after the bite and can include swelling around the wound, pain, and redness of the skin. If any of these symptoms occur following a cat bite, seek medical attention immediately.