A Search For Better Health Topic 6: Antibiotics Biology in Focus, HSC Course

DOT Point(s) identify the role of antibiotics in the management of infectious disease  process information from secondary sources to discuss problems relating to antibiotic resistance world.edu

Introduction Antibiotics play an extremely important role in the management of infectious disease that is caused by bacteria. They are chemicals that are capable of destroying, or inhibiting, the growth of the bacteria that cause disease. indian-pharma.blogspot.com

Introduction Antibiotics are chemicals that target the bacteria without destroying the host and are not at all effective against viruses. Alexander Fleming discovered the first antibiotic, penicillin, in 1928. It was not able to be used at this stage and it was not until the late 1930s, that Howard Florey (an Australian scientist) and Ernst Chan purified penicillin. It then became available for medical use in 1941. gaukartifact.com

Introduction Many infections and diseases that were once considered to be very serious and often fatal were able to be treated successfully with penicillin. This was a revolutionary breakthrough in the treatment of diseases caused by bacteria. www.zazzle.com

Introduction Penicillin is a naturally occurring substance produced by a living thing and since its discovery many synthetic forms of antibiotics have been produced. There are many different types of antibiotics besides penicillin, including tetracyclines, cephalosporins, sulfonamides and erythromycin. www.rightparenting.com

Introduction Broad-spectrum antibiotics, such as sulphonamides, act on a wide range of bacteria and are used when the identity of the bacteria causing the infection is not known. Other types of antibiotics, such as penicillin, act on only one or two types of bacteria and are known as narrow-spectrum antibiotics. www.zotapharma.co.in

Introduction The antibiotics act on the bacteria to destroy them in a number of different ways. Some antibiotics accumulate in the cells of the bacteria and prevent them from forming a new cell wall when they are dividing, for example penicillin. Visit website to watch video: http://besthealth.bmj.com/x/topic/392 706/further-information/5522.html www.soyouwanna.com

Introduction Some antibiotics destroy the cell membrane, thus effectively destroying the bacteria, for example amphotericin. Some antibiotics interfere with protein synthesis so the bacteria are unable to make essential compounds, resulting in the death of the cell. Erythromycin is an example of an antibiotic that acts in this way. www.surgeryencyclopedia.com

How Resistance Evolves When penicillin was first discovered, and then many other antibiotics produced, the threat posed by infectious diseases was greatly reduced and there was a dramatic drop in the number of deaths from diseases that were previously untreatable. medalejandra.blogspot.com

How Resistance Evolves With the widespread use of antibiotics, a problem that threatens the successful treatment of these diseases has developed. Bacteria, during the normal process of natural selection, have evolved strains that are resistant to many, if not all, of the antibiotics that are used to treat infectious disease in the world today. www.soyouwanna.com

How Resistance Evolves The way in which bacteria develop a resistance to the antibiotic can be explained by Darwin’s theory of evolution by natural selection. This theory states that in any population there is variation. In a particular environment, the organisms that have the variation that is best suited to that environment survive and reproduce. www.guardian.co.uk

How Resistance Evolves This produces a population in which most organisms are adapted to survival in that particular environment. When antibiotics are administered to treat a bacterial infection, some of the bacteria present may possess a natural resistance to that particular antibiotic, and so they survive. evolution.berkeley.edu

How Resistance Evolves They then reproduce and can quickly build up a population that is resistant to the antibiotic. In conjunction with this, the bacteria are also capable of passing this resistance on to other bacteria they come into contact with, further building up the population of resistant bacteria. www.anh-usa.org

How Resistance Evolves Antibiotic resistance is being further accelerated by a number of common practices. These include the overuse of antibiotics for treatment of many diseases and not just bacterial diseases. Examples are the prescribing of antibiotics for the treatment of coughs, colds and ‘the flu’. These are diseases caused by viruses, which are not affected by antibiotics. This practice just gives the bacteria more chances to build up populations of resistant strains. www.fitango.com

How Resistance Evolves A very common practice is to only take the antibiotics provided until the symptoms of the particular disease disappear and not finish the whole course. This is also a dangerous practice as not all the bacteria present may be killed before the end of the course of tablets. This allows yet another chance for the bacteria that are more resistant to survive, reproduce and develop populations of resistant strains. www.wired.com

How Resistance Evolves Food-producing animals such as chickens and pigs are fed antibiotics as part of their diet to prevent infections and to promote growth. This widespread use of antibiotics further promotes the formation of antibiotic resistant populations of bacteria. www.bigdutchman.de

How Resistance Evolves The use of cleaning products that contain anti-bacterial ingredients are encouraging the development of antibiotic- resistant strains of bacteria. The quantities of these products used are not enough to kill all of the bacteria, so those that are more resistant will survive, reproduce and form populations that are resistant to antibiotics. au.lifestyle.yahoo.com

Problems With Antibiotics The development of antibiotic resistance has been happening ever since the discovery of penicillin and many antibiotics that were originally hailed as ‘miracle cures’ are no longer effective.

Problems With Antibiotics Micro-organisms that cause diseases once easily cured, such as tuberculosis, have developed resistant strains that are not responding to the cheaper ‘first-line’ antibiotics. As a result of this, the effects of these diseases are now more severe and, because they take much longer to cure, the infectious period is longer, meaning that there is a greater chance of passing on the resistant strain of the micro- organism to other members of the community. www.123rf.com

Problems With Antibiotics When ‘second-line’ or ‘third-line’ antibiotics have to be used they are usually much more expensive and more toxic. The drugs needed to treat multi-resistant tuberculosis are 100 times more expensive than those used to treat the non- resistant forms, and in countries where this is too expensive to use, the disease is untreatable and therefore spreads. udel.edu

Problems With Antibiotics We are now faced with a number of infectious bacteria that are resistant to almost all known antibiotics. Vancomycin is an antibiotic that is used only when all other treatments have failed and even its effectiveness is now being reduced with the emergence of VRE (vancomycin- resistant enterococci) infections and VRSA (vancomycin-resistant Staphylococcus aureus, commonly known as ‘golden staph’). These are the so-called ‘superbugs’, which resist all treatment. www.steyuanpharm.com

Problems With Antibiotics Both of these infections, along with MRSA (methicillin- resistant Staphylococcus aureus), are usually acquired in hospitals and are extremely difficult to treat and eradicate. Many of these infections can only be treated using experimental drugs. careman.wordpress.com

Problems With Antibiotics Antibiotic resistance is a major problem for the treatment of some diseases, as the current trend indicates that in the near future some diseases will have no treatment, unless there is a significant breakthrough in producing more effective drugs. wordoftruthradio.org

Problems With Antibiotics Strategies to slow the development of antibiotic resistance: Antibiotics should only be prescribed for bacterial infections and when it will be of benefit to the patient. The antibiotic prescribed should target the pathogen and not be broad-spectrum. Normal hygiene practices should be strictly adhered to in hospitals. www.fitango.com

Problems With Antibiotics You should not take antibiotics for viral infections such as colds or flu. You should take the whole course of the antibiotic and not stop when the symptoms go away. You should not take antibiotics that are prescribed for someone else. You should not use cleaning products that contain anti-microbial ingredients. www.wired.co.uk

Activity Watch Superbug Video Another video: http://au.news.yahoo.com/today-tonight/latest/article/- /15166259/bacterial-super-bugs/ www.fitango.com

Homework Use the information provided and research other sources to design and produce a brochure that could be given to patients by health-care providers to encourage the responsible use of antibiotics. Your brochure should: ■ describe the causes of antibiotic resistance ■ discuss the problems relating to antibiotic resistance ■ identify strategies that people should use to slow the development of antibiotic resistance. Your brochure should also be ‘attention grabbing’ and contain diagrams and pictures.