When we think of bacteria, we often think of disease, but most bacteria don't have anything to do with humans.
The majority of bacteria that infect humans and cause disease are single-celled organisms that are about 100 times smaller than our own cells.
Bacteria can be produced by themselves and often replicate rapidly within our bodies because of the good food supply.
Bacteria might produce toxins which make us feel ill by damaging our cells and tissues.
An example of a bacterial disease is salmonella, which causes food poisoning and is contracted by eating contaminated food.
Most chickens have to be vaccinated against salmonella, making it relatively rare, but it can still be caught and cause symptoms such as fever, stomach cramps, vomiting, and diarrhea.
Gonorrhea is an example of a sexually transmitted disease (STD) that is passed on through sexual contact.
The best prevention for gonorrhea is avoiding unsafe sex and using barrier methods of contraception like condoms.
For treatment of gonorrhea, common antibiotic penicillin used to cure it without any issues, but now many gonorrhea strains are resistant to penicillin, requiring more expensive antibiotics.