Antibiotics
Uploaded by Admin on Jan 22, 1999
Antibiotics have played a major role in our society thanks to Sir Alexander Fleming's careful observations in 1928. Without it, many lives would be in danger due to infectious diseases.
Antibiotics are chemical substances produced by various species of microorganisms and other living systems that are capable in small concentrations of inhibiting the growth of or killing bacteria and other microorganisms. These organisms can be bacteria, viruses, fungi, or animals called protozoa. A particular group of these agents is made up of drugs called antibiotics, from the Greek word anti ("against") and bios ("life"). Some antibiotics are produced from living organisms such as bacteria, fungi, and molds. Others are wholly or in part synthetic - that is, produced artificially.
Penicillin is perhaps the best known antibiotic. Its discovery and later development is among mankind's greatest achievements. Antibiotics have enabled the medical profession to treat effectively many infectious diseases, including some that were once life-threatening.
How Antibiotics Work?
Antibiotics can be bacteriostatic (bacteria stopped from multiplying) or bactericidal (bacteria killed). To perform either of these functions, antibiotics must be brought into contact with the bacteria.
It is believed that antibiotics interfere with the surface of bacteria cells, causing a change in their ability to reproduce. Testing the action of an antibiotic in the laboratory shows how much exposure to the drug is necessary to halt reproduction or to kill the bacteria. Although a large amount of an antibiotic taken at one time might kill the bacteria causing an illness, such a dose usually would make the person suffer from illness caused by the drug. Therefore, antibiotics are given in a series of smaller amounts. This assures that the bacteria are either killed or reduced enough in numbers so that the body can repel them. When too little antibiotic is taken, bacteria can often develop methods to protect themselves against it . The next time the antibiotic is needed against these bacteria, it will not be effective.
Taking in Antibiotics.
To work against infecting organisms, an antibiotic can be applied externally, such as to a cut on the skin's surface, or internally, reaching the bloodstream within the body. Antibiotics are made in several forms and given in different ways.
Topical. Topical application means "to a local area" such as on the skin, in the eyes, or on the mucous membrane. Antibiotics for topical use are available in the form of powders, ointments, or creams.
Oral. Tablets, liquids, and capsules are swallowed....