Antibiotics, also known as antibacterials, are types of medications that destroy or slow down the growth of bacteria.
The Greek word anti means "against", and the Greek word bios means "life" (bacteria are life forms).
Antibiotics are used to treat infections caused by bacteria. Bacteria are microscopic organisms, some of which may cause illness. The word bacteria is the plural of bacterium.
Contents of this article:
What are antibiotics?
The US National Library of Medicine1 says that antibiotics - powerful medicines that fight bacterial infections - can save lives when used properly. Antibiotics either stop bacteria from reproducing or kill them. "Your body's natural defenses can usually take it from there."
Before bacteria can multiply and cause symptoms, the body's immune system can usually destroy them. We have special white blood cells that attack harmful bacteria. Even if symptoms do occur, our immune system can usually cope and fight off the infection. There are occasions, however, when it is all too much and some help is needed.....from antibiotics.
Alexander Fleming discovered penicillin, the first natural antibiotic, in 1928.
The first antibiotic was penicillin. Such penicillin-related antibiotics as ampicillin, amoxicillin and benzylpenicilllin are widely used today to treat a variety of infections - these antibiotics have been around for a long time.
There are several different types of modern antibiotics and they are only available with a doctor's prescription in most countries.
Overusing antibiotics - There is concern worldwide that antibiotics are being overused. Antibiotic overuse is one of the factors that contributes towards the growing number of bacterial infections which are becoming resistant to antibacterial medications.
According to the CDC (Centers for Disease Control and Prevention), outpatient antibiotic overuse in the USA is a particular problem in the Southeast.
The ECDC (European Centre for Disease Prevention and Control) says that antibiotic resistance continues to be a serious public health threat worldwide. In a statement issued in 19th November 2012, the ECDC informed that an estimated 25,000 people die each year in the European Union from antibiotic-resistant bacterial infections.
New ECDC data has shown that there has been a considerable increase over the last four years of combined resistance to multiple antibiotics in E. coli and Klebsiella pneumoniae in over one third of EU and EEA (European Economic Area) nations. Consumption of carbapenems, a major class of last-line antibiotics, increased significantly from 2007 to 2010.
Antibiotic resistance: how has it become a global threat to public health? Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug, make them resistant," said Alexander Fleming, speaking in his Nobel Prize acceptance speech in 1945. As predicted almost 70 years ago by the man who discovered the first antibiotic, drug resistance is upon us.
How do antibiotics work?
Although there are a number of different types of antibiotic they all work in one of two ways:
- A bactericidal antibiotic kills the bacteria. Penicillin is a bactericidal. A bactericidal usually either interferes with the formation of the bacterium's cell wall or its cell contents.
- A bacteriostatic stops bacteria from multiplying.
What are antibiotics used for?
An antibiotic is given for the treatment of an infection caused by bacteria. Antibiotics target microorganisms such as bacteria, fungi and parasites. However, they are not effective against viruses.
If you have an infection it is important to know whether it is caused by bacteria or a virus. Most upper respiratory tract infections, such as the common cold and sore throats are generally caused by viruses - antibiotics do not work against these viruses.
Image credit: CDC/ Janice Carr/ Deepak Mandhalapu
If antibiotics are overused or used incorrectly there is a risk that the bacteria will become resistant - the antibiotic becomes less effective against that type of bacterium.
A broad-spectrum antibiotic can be used to treat a wide range of infections. A narrow-spectrum antibiotic is only effective against a few types of bacteria. There are antibiotics that attack aerobic bacteria, while others work against anaerobic bacteria. Aerobic bacteria need oxygen, while anaerobic bacteria don't.
Antibiotics may be given beforehand, to prevent infection, as might be the case before surgery. This is called 'prophylactic' use of antibiotics. They are commonly used before bowel and orthopedic surgery.
What are the side-effects of antibiotics?
Below is a list of the most common side-effects of antibiotics:
- Diarrhea - researchers from Stanford University School of Medicine found that a rise in sugars in the gut following antibiotic treatment allows harmful bacteria to get a foothold and cause infection. Harmful bacteria thrive on sugar.
- Feeling and being sick.
- Fungal infections of the mouth, digestive tract and vagina.
Below is a list of rare side-effects of antibiotics:
- Formation of kidney stones (when taking sulphonamides).
- Abnormal blood clotting (when taking some cephalosporins).
- Sensitivity to sun (when taking tetracyclines).
- Blood disorders (when taking trimethoprim).
- Deafness (when taking erythromycin and the aminoglycosides).
Some patients, especially elderly ones, may experience inflamed bowels (a type of colitis) which can lead to severe diarrhea. Clindamycin, an antibiotic used for the most serious infections, commonly has this side effect. However, although much less common, penicillins, cephalosporins and erythromycin might do too.
In August 2012, Scientists from the NY School of Medicine found that babies who are exposed to antibiotics have a greater risk of becoming overweight or obese children. Their study was published in the International Journal of Obesity.
On the next page we look at the possible allergic reactions to antibiotics, how to use antibiotics and we examine how natural processes of microbes are used to fight disease.