Antibiotics: Drugs used to treat some bacterial diseases by killing the bacteria or preventing them from growing. Most current antibiotics were originally derived from microorganisms that occur commonly in the environment.

Bacteria: Microscopic organisms composed of a single cell and lacking a defined nucleus and membrane-enclosed internal compartment.

Cellulitis: An acute inflammation of the connective tissue of the skin, caused by infection with staphylococcus, streptococcus, or other bacteria. It is most common on the face and lower legs, although skin on other areas of the body may sometimes be involved.

Cephalexin: A common antibiotic prescribed for mild to moderately severe infections of the skin, ears, throat, lungs, or urinary tract.

Culture: A test in which the doctor places a sample of blood or other body fluid onto a special growth medium called agar to see if any microbe grows. Certain bacteria, such as chlamydia and strep, and viruses, such as herpes simplex, can usually be identified using this method.

Dicloxacillin: An antibacterial used to treat staphylococcal infections that are resistant to penicillin.

Doxycycline: An antibiotic derived from tetracycline that is effective against many infections.

Infection: A state in which disease-causing microbes or organisms such as bacteria or viruses have invaded or multiplied in body tissues. Some infections do not cause disease because the microbe is quickly killed or hides where it cannot be detected. Some infections do lead to disease.

Infectious Disease: Disease caused by microbes that can be passed to or among humans. It occurs when cells or molecules in a person's body stop working properly, causing symptoms of illness. Many things can make someone more susceptible to disease, including altered genes, chemicals, aging, and infections.

Lesion: A wound or an injury, a localized pathological change in a bodily organ or tissue, or an infected or diseased patch of skin.

MRSA: Methicillin-Resistant Staphylococcus Aureus. Bacteria that cause conditions such as furunculosis, pyemia, osteomyelitis, suppuration of wounds, and food poisoning. The patient is kept in isolation to stop the spread of this infection.

Mutation: A change in the genetic material of a cell that can be harmful, beneficial, or have no effect.

Resistance: The result of microbes changing in ways that reduces or eliminates the effectiveness of drugs, chemicals, or other agents to cure or prevent infections.

Staphylococcous: Parasitic bacteria, usually occurring in clusters, that cause boils and other infections.

Superbugs: Bacteria which have become resistant to specific antibiotics.

Virus: A strand of DNA or RNA in a protein coat that must get inside a living cell to grow and reproduce. It causes many types of illness; for example, varicella virus causes chickenpox, and the human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS). Viruses are not responsive to antibiotics.