Antibiotics

What are antibiotics?

Antibiotics are chemical compounds used to kill or inhibit The growth of bacteria. Strictly speaking, antibiotics are a subgroup of organic anti-infective agents that are derived from bacteria or molds that are toxic to other bacteria. However, the term antibiotic is now used loosely to include anti-infectives produced from synthetic and semi-synthetic compounds.

The term antibiotic can be used interchangeably with the term antibacterial. However, it is incorrect to use the term antibiotic when referring to antiviral, antiprotozoal and antifungal.

History of antibiotics.

Penicillin was the first antibiotic used successfully in treatment. bacterial infections Sir Alexander Fleming first discovered it in 1928, but its potential for treating infections was not recognized until more than a decade later, when Ernst B Chain, Sir Howard Florey and Norman Heatley produced enough purified penicillin to treat patients. In the 1950s, a large number of antibiotics were discovered and manufactured for the treatment of diseases caused by bacterial infection. Over the past 50 years, antibiotics have transformed patterns of illness and death.

Classification of antibiotics.

Antibiotics can be classified in several ways. The most common method classifies them according to their chemical structure, since antibiotics that share the same or a similar chemical structure generally show similar patterns of antibacterial activity, effectiveness, toxicity and allergic potential.

B-lactam antibiotics inhibit the synthesis of the bacterial cell wall. They include:

• Penicillins
• Cephalosporins
• Carbapenems

Penicillins

• Penicillin G
• Amoxicillin
• Flucloxacillin

Cephalosporins

• Cefoxitin
• Cefotaxime
• Ceftriaxone

Carbapenem

• Imipenem

Macrolides inhibit bacterial protein synthesis.

• Erythromycin
• Azithromycin
• Clarithromycin

Tetracyclines inhibit bacterial protein synthesis.

• Tetracycline
• Minocycline
• Doxycycline
• Lymecycline

Fluoroquinolones inhibit bacteria DNA synthesis.

• Norfloxacin
• Ciprofloxacin
• Enoxacin
• Ofloxacin

Sulfonamides block bacterial cells metabolism inhibiting enzymes.

• Trimethoprim + sulfamethoxazole

Aminoglycosides inhibit bacterial protein synthesis.

• Gentamicin
• Amikacin

Imidazole antibiotics inhibit bacterial DNA synthesis.

• Metronidazole

Peptides inhibit the synthesis of the bacterial cell wall.

• Bacitracin

Lincosamides inhibit bacterial protein synthesis.

• Clindamycin
• Lincomycin

The following medications inhibit bacterial protein synthesis.

• Fusidic acid
• Mupirocin

Uses of antibiotics.

Antibiotics only work against infections caused by bacteria. Bacterial infections are much less common than viral infections. Most coughs and colds are viral in origin, so antibiotics should not be prescribed for these. Antibiotics should only be used when absolutely necessary, because:

• There is a growing resistance of bacteria to treatment.
• Resistant bacteria are selected through the use of antibiotics.
• Antibiotics can have serious side effects in some people.

Some common bacterial infections that require antibiotic therapy include:

• Staphylococcal skin infections, for example impetigo (school sores)

• Streptococcal skin infections, eg cellulitis.

• A little ear and breast infections
• 'Streptococcus' – sore throat caused by Streptococcus

If these infections are left untreated, the resulting illness can be serious and even fatal.

In severe bacterial infections where patients may be hospitalized, a broad-spectrum intravenous antibiotic (one that is active against many different bacteria) is often given to begin treatment. As soon as laboratory tests confirm the infecting bacteria, the antibiotic should be changed to one that is active against specific bacteria. After 48 hours of intravenous treatment, if there is clinical improvement, the patient can be switched to an oral form of the antibiotic.

antibiotic resistance

Overuse and inappropriate use of antibiotics has led to antibiotic resistance. Bacteria that were once susceptible to antibiotics have developed ways to survive drugs meant to kill or weaken them. This is also known as antibacterial resistance or drug resistance. Some diseases such as tuberculosis, gonorrhea, and childhood bacterial ear infections, which were once easily treated with antibiotics, are now becoming difficult to treat as the bacteria have become resistant to these medications. About 70% of the bacteria that cause infections in hospitals are resistant to at least one of the antibiotics most commonly used to treat infections. Methicillin (methicillin) resistant Staphylococcus aureus (MRSA) is a particular problem for patients with skin diseases, ulcers and surgical wounds.

Doctor's responsibility

• Only prescribe antibiotics if they are bacterial infection present
• Prescribe at approved dosage and duration or as recommended by experts
• Educate the patient about the importance of completing their course of antibiotics as directed.

Patient Responsibility

• Understand that not all infections are bacterial and that not all bacterial infections will go away with antibiotics (eg, folliculitis)
• Take antibiotics exactly as directed (i.e., with or without food, etc.)
• Be sure to finish the course of antibiotics.

Side effects of antibiotics.

Antibiotics are associated with many side effects, including cutaneous Adverse reactions. Some side effects are class related, but most reactions are specific to the agent in that individual.

Here are some common problems with antibiotics:

• Allergy to certain antibiotics or classes of antibiotics (eg, allergy to penicillin)
• Many antibiotics cause gastrointestinal problems (eg, diarrhea, vomiting, nausea).
• Antibiotics kill not only their targets, but also othersorganisms that live in and on our body (flora) to prevent other diseases (e.g. oral and/or vaginal thrush)
• A variety of skin rashes may occur, which can be mild (e.g., hives) or devastating (e.g., toxic). epidermal necrolysis).