Let's just put it this way, animals can't live without bacteria. I know that sounds crazy, but there are different kinds of bacteria. The kind that you and I think about a lot are hetatroph bacteria. They cause us to get sick. Autotroph bacteria on the other hand live in you and me inside our intestines. They also live in animals. If we and they didn't have them, we'd die. Hope this helps!
Bacteria is everywhere so yes, it's on animals, in dirt, in the air, on and in food, in and on our bodies and is most often beneficial or benign.
Some bacteria are beneficial to their hosts.
Animals that chew their cud (aka, 'ruminate') are called ruminants. This is beneficial to these animals because they have bacteria in their stomachs that digest the various plant materials the ruminant eats. To help the bacteria digest the plants, the ruminant brings up a wad of plant material (called the cud) and chews it thoroughly to mechanically break down the tough structural fibers of the plant. The ruminant then reswallows the cud, the bacteria digest the plant and both the bacteria and the cow get their necessary nutrients from the plant.
Fungus
Bacteria and fungi can be harmful as they can cause diseases in humans, animals, and plants, such as infections and decay. However, they are also beneficial as they play important roles in nutrient recycling, decomposition, and fermentation processes. Some bacteria and fungi are used in food production, bioremediation, and the production of antibiotics.
Salmonella
Bacteria can be both harmful and helpful. Harmful bacteria can cause diseases in humans, animals, and plants. However, some bacteria are beneficial and play important roles in processes like digestion, nutrient cycling, and decomposition.
nitrogen fixing bacteria bacteria of decay nitrifying bacteria denitrifying bacteria
bacteria or decomposers
Vaccines
Some bacteria are beneficial to humans, and some bacteria are harmful to humans.
Bacteria can be harmful by causing infections and diseases in humans, plants, and animals. However, some bacteria are beneficial and play essential roles in processes like decomposition, nutrient recycling, and food fermentation. Additionally, beneficial bacteria in our bodies help with digestion, vitamin synthesis, and immune system function.