Antibiotics are such a basic, everyday part of health care, it is easy to forget that they were unknown before the late 1920s. The first antibiotic, penicillin, was discovered in 1928 by Alexander Fleming, a scientist working at St Mary’s Hospital, London, while the first commercially available antibiotic was developed in Germany in 1932. Antibiotics were first used widely during World War II.
Reasons for Antibiotic Therapy
Antibiotics are prescribed to treat infections caused by bacteria. They are sometimes referred to as “antibacterials” to emphasize this, and to distinguish them from drugs that target other organisms such as viruses and fungi.
Common conditions that can be treated with antibiotics include tonsillitis, pneumonia, food poisoning due to bacteria, the skin infection impetigo, and bacterial sexually transmitted infections such as chlamydia. Antibiotics are usually taken as tablets, or are sometimes administered in the form of an ointment or eye drops. In severe infections, they may need to be injected directly into a vein.
Antibiotics are also given as prophylaxis – that is, to prevent an infection occurring. Prophylactic antibiotics are often given before surgery on the bowel or a broken bone, and are helpful in people who have had their spleen removed and are therefore less able to fight infection. People with heart valve disease are prone to developing an infection of the heart (endocarditis) after undergoing dental procedures, and are given antibiotics by their dentist for this reason.
Antibiotics have no effect on very common illnesses such as flu, coughs and colds, and mild sore throats. These infections are caused by viruses, not bacteria.
Cephalosporin, Tetracycline, Quinolone – Antibiotic Types
The first antibiotic, penicillin, has become less useful over the years due to increasing resistance to its effects among bacteria. Many new classes of antibiotics have been introduced in the wake of Fleming’s discovery, but these too are vulnerable to the emergence of resistance. Pharmacologists developing new antibiotics must strive constantly to stay one step ahead of the bacteria they are fighting.
- Bactericidal antibiotics kill infecting bacteria by damaging their cell wall or membrane, or by interfering with essential bacterial enzymes.
- Bacteriostatic antibiotics slow the progression of an infection by disrupting the proteins that bacteria need to grow.
- Broad-spectrum antibiotics are effective against a wide range of different types of bacteria.
- Narrow-spectrum antibiotics target specific types only.
- Cephalosporins were among the earliest antibiotics, being first developed in the 1940s. They are divided into “generations,” from first to fifth, indicating the order in which they were introduced and their increasingly broad-spectrum effects.
- Tetracyclines have been particularly affected by bacterial resistance, but are still useful for certain infections. They are most commonly used to treat acne.
- Quinolone antibiotics were introduced in the 1960s and are often prescribed for infections of the respiratory tract and for prostatitis.
Other classes of antibiotic include the sulfonamides, nitrofurans, carbapenems and aminoglycosides. Newer types of penicillin are also available, based on the original drug from 1928.
Antibiotic Allergy and Side Effects
Like all drugs, taking antibiotics carries a small risk of side effects. Most people experience no problems, but a few may suffer diarrhoea, nausea and/or vomiting. In rare cases, antibiotics may cause liver or kidney disease, colitis, blood disorders or sensitivity to sunlight.
As well as fighting unwanted infections, broad-spectrum antibiotics can reduce the numbers of “friendly” bacteria that normally live in the body, relative to the populations of other micro-organisms. Any alteration in the balance of this “microflora” can lead to an attack of thrush (candidiasis), caused by the yeast Candida. Commonly affected sites include the mouth, throat and genitals.
Some people are allergic to penicillins, cephalosporins or other types of antibiotic. An antibiotic allergy can cause a skin rash, swelling of the face or, in the most severe cases, an anaphylactic reaction (low blood pressure and difficulty breathing), which can be fatal. Anyone who has had a reaction in the past should always discuss this with their doctor when being prescribed antibiotic therapy.
References:
Antibiotics. Accessed 29-01-11
Antibiotics. Accessed 29-01-11
Antibiotics, Penicillins. Accessed 29-01-11
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
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