WHY DOES EVOLUTION MATTER NOW?

Activity 1: Evolution and Antibiotic Resistance

When people go to the doctor's office, they expect to be cured. They don't like to be told, "Go home, drink lots of fluids and rest, and you will get better." They want a more proactive approach. Often, doctors prescribe antibiotics just to make their patients happy, even if the antibiotics cannot treat the illness at hand. As a result, antibiotics become more prevalent, the microbes they attack are more likely to develop resistance, and over time the antibiotics become ineffective. Learn about why some diseases have become antibiotic-resistant and how you can help address the problem.

Part A: Misuse of Antibiotics

1.

View "Why Does Evolution Matter Now?" Travel inside a Russian prison to see the impact of evolution on the lives of the inmates and the surrounding community. This video describes the transmission of tuberculosis and the evolution of multiple drug-resistant strains of TB.

2.

Answer the following questions about the video segment:

• Why is the Russian prison system considered to be "ground zero" in the fight against TB?

Because the Tuberculosis is so contagious in the prison’s air and if somebody enter and breaths that air, he could infect the Tuberculosis.

• What is responsible for the evolution of TB strains that are resistant to multiple drugs?

The same medication that “treats” a patient is the responsible of mutations of the Tuberculosis because that medication can kill a great percent of Tuberculosis, but the bacteria that remain change and become exempt of that medication.

• How does the misuse of antibiotics affect the evolution of disease-causing bacteria? Use the theory of natural selection to explain the growing resistance to antibiotics.

If the bacteria it’s exempt of the different drugs that a patient takes, it could reproduce a million times and infect too much the patient.

• Why should we care about a resistant strain of TB in Russia?

We have to take care of the changes of the Tuberculosis in Russia because in some years later or in a near future it could be worse to the health of the million people that live in hearth.

Part B: Antibiotic Resistance in Your Neighborhood

1. Gather information about the use and misuse of antibiotics in your own neighborhood. Print the Evolution and Antibiotic Resistance: Survey form (pdf), or obtain a copy from your teacher. Try to find at least five people of different ages to survey.

Evolution and Antibiotic Resistance: Survey

1. Have you taken any antibiotics in the past year? Why were antibiotics prescribed for

you? Did you or your doctor know that you had a bacterial infection?

2. Did you take the medication at the dosages and intervals prescribed and take it for

the entire recommended course of treatment? If not, why not?

3. Do you know why it is important to finish all prescriptions, even if your symptoms

have cleared up?

4. Do you think antibiotics are over prescribed by doctors? Explain.

Person 1:

1) Yes, I have, because I had a vesicle’s surgery. We didn’t know because it was for prevention.

2) Yes; I did and took all the drops that I had to take.

3) Yes, I know. Because always stay in the organism parts of the virus, even if your symptoms have cleared up.

4) I don’t think so. I think that they give theme when is necessary.

Person 2:

1) Yes, I have, because I had malaise, vomit and low pressure. Yes we knew.

2) Yes, I did and took all the drops.

3) Yes, I know.

4) No, I don’t. I think that they don’t do tests with the organism.

Person 3:

1) Yes, I have, because I had otitis. Yes, we knew.

2) Yes, I did.

3) Yes, it is important because if the doctor prescribed for you, the antibiotics would be important.

4) No, I don’t. They prescribed for you only if you need them.

Person 4:

1) Yes, I have, because I had flu. Yes, we knew.

2) Yes, I did.

3) Yes, I do. Is very important to have a continuity.

4) No, I don’t.

Person 5:

1) Yes, I have, because I had a laryngitis infection. Yes, we knew.

2) Yes, I did and took oll the drops.

3) Yes, I do. Because if the doctor prescribed for you, the antibiotics would be important.

4) No, I don’t. The doctors only give them when is necessary.

2. Ask local health professionals the following questions about antibiotics:

• Unfinished prescriptions: If you have a pharmacy near your house, ask the pharmacist why it is important to finish all prescriptions. If you have access to a doctor, ask your doctor why it is important.

It is very important to finish the medical prescription to creating a resistance to antibiotic. It is very important to cure the pathology.

• Prevalence of antibiotics: Ask a doctor how often he or she prescribes antibiotics.

The antibiotics have to be prescribed only when is necessary.

• Prevalence of infectious disease: Contact your local health department to gather data about the incidence of infectious disease over the past few years.

During winter respiration and pharynx pathologies are more frequent. During summer otology’s pathologies. In the spring allergies are more frequent.

3. Summarize the results of your survey. Do you think the misuse of antibiotics is a problem in your community? Why or why not? Report your findings in class.

No, I don’t. I think, from my interviews, my community understands that the antibiotics have to be used with caution and the doctor prescription has to be followed to avoid an antibiotic – resistance. I can observe too that the doctors are aware of this, because everyone in my community said:

“The doctors give the antibiotics only when is necessary”.

Part C

4.

Antibiotic Resistance

The antibiotic resistance is the capacity of a microorganism to resist the effects of an antibiotic. The resistance takes place (is produced) naturally for natural selection across mutations produced by random, but also a population can be induced artificially by means of the application of a selective pressure. As soon as the genetic information is generated, the bacteria can transmit the new genes across horizontal transference (between (among) individuals) for exchange of plasmids. If a bacterium carries several genes of resistance, he is named multirresistente or, informally, superbacterium.

Reasons

The antibiotic resistance it is a consequence of the evolution route the natural selection. The antibiotic action (share) is an environmental pressure: those bacteria that have a mutation that allows them to survive will reproduce. They will spend (pass) this feature to his(her, your) descent, which will be a totally resistant generation.

Natural selection is an evolutionary mechanism that is defined as the differential reproduction of genotypes within a biological population. In its initial form, the theory of evolution by natural selection is the great aportación1 of Charles Darwin (and, independently, by Alfred Russel Wallace), was subsequently restated in the current theory of evolution, the modern evolutionary synthesis. In Evolutionary biology is considered the main cause of the origin of species and their adaptation to the environment.

The classical formulation of natural selection states that the conditions of an environment support or hinder, ie select the reproduction of living organisms according to their peculiarities. Natural selection was proposed by Darwin as a means to explain biological evolution. This explanation is based on two premises. The first one says that among the descendants of an organism is a random variation, not deterministic, which is partly heritable. The second premise holds that this variability can lead to differences in survival and reproductive success, making some emerging features could spread in the population. The accumulation of these changes over the generations would produce all developmental phenomena.

Until recently, research efforts and development (R & D) have provided a timely new drugs to treat bacteria that have become resistant to older antibiotics. This is no longer true today. The potential crisis is the result of declining budgets for R & D in industry, government inactivity and increased prevalence of resistant bacteria. Physicians treating infectious disease is concerned about the prospect of not having effective antibiotics to treat severely ill patients in the near future.

Research into new antibiotics is almost stopped. Major pharmaceutical companies are losing interest in antibiotics because they are both beneficial and medicines that treat chronic (long term) and those related to the style of life.

The resistance problem demands that a renewed effort is made to search for antibacterial agents effective against bacterial pathogens resistant to current antibiotics. One of the possible strategies towards this goal is a rational pursuit of bioactive phytochemicals. The plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their derivatives by substitution of oxygen, such as tannins. Most are secondary metabolites, which have been isolated at least 12,000, a number that is estimated to be less than 10% of the total. In many cases, these substances serve the plant as defence mechanisms against predation by micro organisms, insects and herbivores. Many of the herbs and spices used by humans to season food containing medicinal ingredients, including some that are active antibacterial.

Traditional healers have long used plants to prevent or cure infectious diseases. Many of these plants have been investigated scientifically for antimicrobial activity and has proven that a large number of plant compounds inhibit the growth of pathogenic bacteria. A number of these agents appear to have structures and modes of action different from antibiotics in use, suggesting that cross-resistance with them is minimal. For example, the combination of 5'-metoxihidnocarpina and berberine in Goldenseal and herbs such as Berberis vulgaris may block the active pumping of MDR that causes multidrug resistance. This has been tested for Staphylococcus aureus.

Prevention

Wash hands properly reduces the chance of infection or spread infection. Wash thoroughly and avoid handling both raw foods like fruits, vegetables, raw eggs and undercooked meat with cooked foods can also reduce the possibility of infection. High-risk activities include unprotected sex, Use of equipment in gyms or public places, being a patient in a hospital or nursing home, be a recluse, going to the hairdresser, share personal products (cosmetics, lotions, linens, toothpaste, headphones, nail clippers, shampoo).

Avoid the use of antibiotics, in some situations, may also reduce the possibility of infection by bacteria resistant to antibiotics. One study found that use of fluoroquinolones was clearly associated with infection by Clostridium difficile, which is a major cause of nosocomial diarrhoea in EE.UU. And a major cause of death around the world.

Vaccines do not suffer from the problem of resistance because they increase the body's natural defences, while the antibiotics operate separately from the body's normal defences. This does not prevent new strains may escape immunity induced by vaccines.

Although theoretically promising, anti-Staphylococcus vaccines have shown limited efficacy due to immune variation between different species of Staphylococcus and the limited duration of effectiveness of the antibodies produced. Is currently under development and testing of more effective vaccines.