Antibiotics

What Are Antibiotics? How Do Antibiotics Work?

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.

Such illnesses as syphilis, tuberculosis, salmonella, and some forms of meningitis are caused by bacteria. Some bacteria are harmless, while others are good for us.

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.

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 industrialized countries.

According to Medilexicon's medical dictionary, Antibacterial means:

"Destructive to or preventing the growth of bacteria."

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.

According to the ECDC (European Centre for Disease Prevention and Control), 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.

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 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.

If antibiotics are overused or used incorrectly there is a chance 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.

Allergic reactions to antibiotics

Some patients may develop an allergic reaction to antibiotics - especially penicillins. Side effects might include a rash, swelling of the tongue and face, and difficulty breathing. If you have ever had an allergic reaction to an antibiotic you must tell your doctor and/or pharmacist. Reactions to antibiotics can be very serious, and sometimes fatal - they are called anaphylactic reactions.

Use antibiotics with extreme caution and ensure you inform your doctor/pharmacist if:

• You have reduced liver or kidney function.
• You are pregnant
• You are breastfeeding

Antibiotics may clash (interact) with other medicines

If you are taking an antibiotic do not take other medicines or herbal remedies without telling your doctor first. OTC (over the counter, non-prescription) medicines might also clash with your antibiotic.

Penicillins, cephalosporins, and some other antibiotics may undermine the effectiveness of oral contraceptives. If the antibiotic has caused diarrhea/vomiting the absorption of contraceptives may also be disrupted. If you are taking any of these drugs you should consider taking additional contraceptive precautions.

How to use antibiotics

Antibiotics are usually taken by mouth (orally); however, they can also be administered by injection, or applied directly to the affected part of the body.

Most antibiotics start having an effect on an infection within a few hours. It is important to remember to complete the whole course of the medication to prevent the infection from coming back. If you do not complete the course, there is a higher chance the bacteria may become resistant to future treatments - because the ones that survive when you did not complete the course have had some exposure to the antibiotic and may consequently have built up a resistance to it. Even if you are feeling better, you still need to complete the course.

Some antibiotics should not be consumed with certain foods and drinks. Others should not be taken with food in your stomach - these would normally be taken about an hour before meals, or two hours after. It is crucial that you follow the instructions correctly if you want the medication to be effective. If you are taking metronidazole do not consume alcohol. Dairy products should not be consumed if you are taking tetracyclines, as they might affect the absorption of the medication.

Penicillins

Penicillins are a certain collection of antibiotics that eliminate infection causing bacteria. Also known in short as pen or PCN, they originate from a type of fungi called Penicillium fungi. They are used in the treatment or prevention of many different bacterial infections, usually caused by Gram-positive organisms.

They are well known in medicine as they are one of the first types of antibiotic used for major infections and diseases, and are still used regularly in modern medicine. Penicillins are all β-Lactam (Beta-Lactam) antibiotics, which are antibiotic molecules with a β-Lactam nucleus.

There are a number of penicillin types, that react to bacteria in a variety of degrees, some of these are:

• ampicillin
• amoxicillin
• flucloxacillin
• phenoxymethylpenicillin

According to Medilexicon's medical dictionary, penicillin is:

1. Originally, an antibiotic substance obtained from cultures of the molds Penicillium notatum or P. chrysogenum; interferes with cell wall synthesis in bacteria.

2. One of a family of natural or synthetic variants of penicillic acid. They are mainly bactericidal, are especially active against gram-positive organisms, and, with the exception of hypersensitivity reactions, show a particularly low toxic action on animal tissue.
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Back Ground (History)of Penicilln

Penicillins were originally discovered by Ernest Duchesne (a medical student) in the late 19th Century, and then re-discovered for its antibiotic properties by Alexander Fleming in 1928. He realized this when a sample of a certain bacteria (Staphylococcus) became contaminated by some mold (Penicillium fungi) and that all bacteria cells closest to the mold were dying.

It was with further testing that Fleming realized the mold was actually creating a bacteria destroying substance, which he later named penicillin. This was the catalyst that brought about the future of antibiotic discovery.

Before Fleming's discovery, there were others that came across the bacteriostatic effects of penicillium fungi (such as Duchesne, mentioned above), but at the time knowledge of bacterial and viral infections was not strong enough to support any practical use to this finding.

How penicillins work:

Our immune system is usually enough to destroy harmful bacteria, as we have white blood cells that attack them before they multiply. Even if symptoms do occur, our immune system can usually fight off the infection itself. Nevertheless there are instances where it is all too much for our bodies, and they need help which is where antibiotics come in.

Bacteria are constantly rebuilding their cell walls (known as peptidoglycan synthesis), which is how they protect themselves and maintain their structure. Penicillins work by damaging and penetrating these cell walls, thus killing the bacteria cells. Bacteria can build a resistance to this by making β-lactamase , which defends the bacterial walls by assaulting the β-lactam ring. This defense can be counteracted by combining the penicillins with β-lactamase inhibitors.

Penicillins Use for :-

Penicillins were one of the first drugs used to treat diseases such as syphilis, and are still in great use in modern day medicine. Many kinds of bacteria however are now penicillin resistant.

There are three main instances where penicillins would be used, these are:

• To help fight off a bacterial infection e.g. tonsillitis
• To prevent infection for someone with a weakened immune system due to existing illness/condition e.g. someone with sickle cell disease
• To give someone's immune system help if they are undergoing treatment which could leave them vulnerable to infection.

Penicillins Side-effects :-

Like a lot of drugs, penicillins have adverse effects, there are some common side effects and some rare.

The common side effects can occur in no more than 10% of those that take penicillins, they include:

• diarrhea
• feeling and being sick
• rashes and other types of less serious allergic reactions

The rarer side effects, which occur in less than 1%, can be:

• dizziness
• inflammation of the liver (hepatitis)
• kidney inflammation (nephritis)
• dermatitis
• convulsions/fits (especially in epileptics)
• erythema
• thrush
• blood disorders

Contrindication Penicillins :-

When a number of medicines are used in sync, one may prevent or hinder the other(s) from working properly. For instance, some penicillins are known to weaken the effectiveness of oral contraceptives. This is called drug-drug interaction.

The most common medicines or substances that cannot be taken alongside penicillins include:

• Allopurinol - when taken with ampicillin or amoxicillin, there is risk of developing a non allergic rash.
• Oral Contraceptives - can impede their effectiveness when used alongside penicillins, thus increasing the chance of getting pregnant.
• Methotrexate - penicillin decreases the body's ability to rid itself of this methotrexate, this can lead to serious complications.

Substances and medicines that can be taken with penicillins are:

• Probenecid - this drug can hinder the body's capacity to remove penicillin, however this is not necessarily a problem. Using the two drugs together would increase the amount of penicillins in the bloodstream and improve their effects.
• Alcohol - there are no complications caused by consuming alcohol while taking penicillins.

Penicillins user Guide:-

Penicillins are normally consumed orally (through the mouth). However, some types can only be injected. Examples of these are:

• ticarcillin plus clavulanic acid (Timentin)
• temocillin (Negaban)
• piperacillin plus tazobactam (Tazocin)
• benzylpenicillin (Crystapen)

Before taking penicillin there are some factors to consider, such as:

• Being allergic to penicillin - if this is the case penicillin should definitely not be taken. This applies to all types of penicillin - if you have been allergic to one you will be allergic to them all. If you have been allergic to other β-Lactam antibiotics, you will be allergic to penicillin
• Having a history of allergies - people with previous allergies, such as eczema or asthma are at greater risk of going into anaphylactic shock if they take penicillins. This risk is still small but don't be afraid to check with your doctor if you have had any allergies in the past or still do.
• Are pregnant and breastfeeding - only phenoxymethylpenicillin is not guaranteed safe when pregnant so should only be used if completely necessary, most of the other types are fine. When breastfeeding it is important to take note that phenoxymethylpenicillin can pass into the breast milk, this can affect the baby.
  
  Some penicillins are mixed with clavulanic acid and again shouldn't be used when pregnant and breastfeeding unless it is the only option.
• Suffering from liver or severe kidney problems - penicillins should be taken with care.

It is crucial that the whole course of penicillin is completed to prevent the infection returning. If the course is not completed, the chance of the bacteria becoming more resilient to future treatments is greatly increased. This is due to the bacteria left over from the incomplete course of treatment building up resistance to the penicillin as it has had previous exposure. This shows how important it is to finish the course (even if feeling better) and kill any remaining bacteria.

If a dose is ever missed, you should try to take the dose as soon as possible and then continue back to the normal course. If you haven't realized by the time for the next dose, the forgotten dose should be skipped altogether as it is important a double dose is not taken. If more than one dose has been missed, it is worth contacting your doctor for advice on how to proceed.