The tetracycline antibiotics, like the penicillins, are among the most useful and important antibiotics. They are effective against a wide variety of bacteria and rickettsia. Most tetracyclines should not be taken with food or milk because their effectiveness will be greatly diminished. In addition, the tetracyclines are used to treat Rocky Mountain Spotted Fever, acne, and the plague. In fact, it is used much like penicillin G and is a good alternative for people who are allergic to penicillins.
Polypeptide antibiotics are too toxic to be used generally in the body.
However, they are not toxic if used topically, or on the surface of the body. There are a few of each of these types of antibiotics that are incorporated into creams and ointments for the treatment of skin infections that usually result from relatively minor cuts and abrasions. Examples of fungal infections are athlete's foot, ringworm, jock itch, and vaginal yeast infections. These are usually treated by the application of antifungal drugs to the affected area. This is a very important point which cannot be overemphasized.