FAQ – Dose: Antibiotic Resistance & Consequences (N. Qureshi Remix)

Posted by | July 24, 2009 | RESOURCES, TEXTBOOK, UNIVERSITY+ | No Comments

Editors note – Over the next few months we will be bringing you some of the best FAQs from last year’s ASIC 200 class. They are a great way to get an introduction to many of the arts/science issues that our planet faces. Check back every Friday for a new one! – Geoff

Dosage Instructions: Long term side effects of distributed report may include but are not limited to increased awareness and the prevention of a global catastrophe.

So, first of all, what exactly to antibiotics do?

Well, antibiotics are really just chemicals that either kill bacteria or stop their growth, while at the same time providing as little damage to the host (e.g. humans) as possible, if any [11]. However, although side effects or allergies are possible, on the most part antibiotics are gentle cures to bacterial infections [11]. That said, it is essential to note that antibiotics only intended to treat infections caused by bacteria, not those caused by viruses.

curtain

Penicillin was the first effective antibiotic ever used, and it was powerful against many different types of bacteria [14]. Its use first became popular for the treatment of WWII wounds [14]. However, there was already evidence of bacteria being able to resist its effects a mere few years after this antibiotic’s mass production [14].

What is antibiotic resistance, and why should I be concerned with it?

Antibiotic resistance is the capability of an organism to survive the harmful effects of antibiotics [6]. Experts say that although this process itself is inevitable, there ways in which we can significantly prevent antibiotic organisms from thriving and becoming a global threat; methods such as public education and infection control [14][2][3].

Even today, infectious diseases continue to be the leading cause of death in the world, and this is especially true in developing countries, where access to adequate health resources are often deficient [10][13]. So you see, evidence of bacteria becoming more and more resistant to antibiotics creates increasing obstacles for treatment of certain infections.

How exactly do bacteria “learn to” survive antibiotics?

It all comes down to certain events that change the DNA, or genetic sequence, of bacteria. You see, all living organisms have DNA, a sequence of molecules called nucleic acids, which serve as the blue-print of a cell’s function [5].

For example, DNA dictates which proteins or enzymes are made, and thus changing a cell’s DNA through various means can potentially change which proteins are produced by that cell [5]. Proteins are important functional molecules, where different proteins have different roles in a cell [5].

Bug Dealer

So if a bacterium is able to change or add to its DNA through a certain mechanism, it may be able to gain a new function [4]. DNA can mutate (i.e. change spontaneously), or bacteria can uptake new DNA from components of dead bacteria in the environment [4]. Another way a bacteria can acquire new DNA is through a process called ‘conjugation’ [15], where DNA can be transferred directly from one bacterium to another [16]. This results in ‘transformation’, or the incorporation of new DNA into the bacteria’s existing DNA [16].

Most importantly, new functions gained may be those that allow a bacterium to become ‘resistant’ to antibiotics, such as by inactivating antibiotics, decreasing antibiotic uptake, excreting the antibiotic before it has a chance to harm the cell, or even using the antibiotic to its advantage, as a substance that promotes growth, for example [10].

Is there anything being done locally to take action against this issue?

Currently, the Canadian Committee on Antibiotic Resistance (CCAR) is developing a National Action Plan to address some of the problems that are related to antibiotic resistance in Canada [1]. Some of the main issues that are being focused upon include [1]:

* Putting into place more stringent ways to observe, monitor, and contain infections by organisms that have multiple antibiotic resistance (when dealing with resistance for both human and animal pathogens);
* Ensuring the appropriate use of antibiotics in both humans and animals by the above control & safety mechanisms;
* Enhancing methods to prevent infection, especially in hospitals;
* Distinguishing and pursuing specific areas of research;
* Spreading awareness through a widespread information program across all disciplines.

In addition, an organization called CHICA-Canada (Community & Hospital Infection Control Association of Canada) plays a powerful role across the country in spreading awareness of infection control through education, awareness and encouraging research [2] [3].

From a global perspective, how is antibiotic resistance affecting society?

The treatment of urinary tract infection (UTI) has become increasingly difficult in countries such as India due to multiple antibiotic resistance by its primary cause, the bacterium Escherichia coli, more commonly known as E. coli [7]. The antibiotics, namely ciprofloxacin, SXT and amoxicillin, that were normally used to treat this infection, now show dramatic lack of response from this bacterial strain [7].

How has antibiotic resistance come to be such a serious issue in the world today?

The development and continuing severity of antibiotic resistance has been perpetuated through the over-prescription, the widespread use, and the lack of dose completion of antibiotics [9]. All of these may cause bacteria to undergo a process called ‘selection’ [9]. This is where an antibiotic would initially kill the less fit bacteria, and not finishing one’s antibiotic dose would ‘select for’ or allow the really ‘strong’ and persistent remaining bacteria (those few who may be a little more resistant and need longer to die) to survive and multiply [9] [14]. Their progeny will demonstrate identical resistance qualities, and any additional changes to their genes could result in a few being even more resistant to the antibiotic [9]. Thus, this process goes on.

Also, since prescribing antibiotics for viral infections has no effect on viruses, this just means that any traces of antibiotics taken would get released into the environment, where it may encounter infectious bacteria and repeat the selection process described above [14]. Other instances where antibiotics may get released into the environment are when they are mass distributed to animals [11].

Hold on!! Aren’t antibiotics necessary to treat animals when they fall ill?

You see, in agriculture, antibiotics have three main functions [11]. First, as mentioned, they are used to treat sick animals. However, this accounts for only 10-15% of antibiotics used in agriculture. Second, about 30% are also used to prevent disease, a term we call ‘prophylaxis’ [11]. The need to do this is more important than many people realize. Let’s say you happen to have a rather stringent boss at work who makes you work on your feet for 18 hours a day, seven days a week, conducting interviews and making presentations with never a moment’s rest, and in a heavily metropolitan setting. That kind of stress is likely to take a toll on your immune system, or your body’s natural ability to fight off diseases, right? Well it’s a similar story with animals on farms. Instead of wearing business suits, running errands and meeting important people, they serve to constantly build up their bodies to produce meat, eggs or milk. Because of this kind of physical stress and crowded living conditions, their ability to fight off disease is more compromised than their more relaxed counterparts [11]. Thus, from the perspective of farmers, financially, it becomes doubly important to prevent disease and keep animals alive as long as possible. The means to do so that have been undertaken have been through the use of antibiotics.

Third, using antibiotics as growth promoters, or for weight gain in animals, has been the most controversial aspect of its agricultural use, and accounts for anywhere from 15% to 50% of agricultural antibiotic use [11]. You may ask, “How do antibiotics make animals gain weight?!”. I must say, it is a complex answer and has a number of theories, but has much to do with the animals staying healthy, fit and disease free 11. And, mind you, the weight gain itself is minimal, at most 4-5%, although even that little is extremely significant in terms of farming practices [11].

The reason that the agricultural use of antibiotics is so controversial boils down to the fact that society just can’t agree on the definition of ‘therapeutic’ or ‘non-therapeutic use’ of antibiotics in animals. Or in other words, whether antibiotics are really only being used in life-or-death situations. Some say yes for one application, whereas others would disagree.

A significant issue in the world today is that antibiotic resistance could continue to develop to the point where some bacteria are resistant to all antibiotics [9]!

So, are there any other diseases where this issue has had an impact?

As mentioned, genetic change of bacteria, antibiotic over-use and incompletion are causing strains of Staphylococcus aureus to become resistant to multiple antibiotics [9]. A major example of this is an infection called MRSA [9] [14]. Typically the normal bacterial strain is resistant to perhaps a couple of antibiotics but, with regard to MRSA, it is resistant to many more [9].

What is ‘MRSA’?

MRSA stands for ‘methicillin-resistant Staphylococcus aureus’, which is just a fancy way to describe a type of bacteria called Staphylococcus aureus that has become resistant to a number of antibiotics, including one called methicillin [9]. This is only one example of a bacterial strain that has become resistant to multiple antibiotics; others include Vancomycin Resistant Enterococcus (VRE), and Extended Spectrum Beta Lactamase (ESBL) [2].

MSRA

Normally, the bacterium Staphylococcus aureus is harmless, and lives on the surface of people’s skin and nose of some people [9.] It is when it enters a cut or wound of someone who is already very ill or recovering from surgery, that it may cause infection because that individual’s immune system cannot fight off invading organisms too well due to their circumstance [9]. This kind of infection begins with deep skin lesions, and upon entering the bloodstream, can infect the lungs, skin, heart or bones [8].

Why are antibiotic resistant organisms (AROs) particularly important in hospitals?

Well, in hospitals antibiotic resistant organisms pose as a serious threat in three ways [9]:

* Most patients in hospitals have very poor immune systems and thus have the potential to become infected with other pathogens that are brought into contact with them, especially those as lethal or as powerful as organisms that are resistant to multiple antibiotics.
* Secondly, medical apparatuses such as an intravenous drip or a catheter in patients can serve as portals of entry through which AROs or any other infectious agent can infect them.
* Often, patients are treated in close living quarters, which significantly increases the chances of AROs spreading among patients. That is why keeping patients known to be infected with any AROs are isolated immediately.
* Lastly, and perhaps most ominously, hospitals are unfortunately an ideal environment for bacteria such as Staphylococcus aureus to easily come across a great number of antibiotics. Consequently, AROs can develop through genetic selection and survival of the fittest bacteria.

How is MRSA treated?

As you can imagine, it is much more difficult to treat MRSA since it is resistant to so many different antibiotics [9]. But it’s important to note that MRSA is not resistant to every single antibiotic out there (most strains can still be treated with a few antibiotics, such as vancomycin and teicoplanin [9]). The terrifying thought, though, is what will happen if MRSA becomes resistant to those last couple of antibiotics?

As mentioned, patients in hospitals or individuals with poor immune systems are at a higher risk of infection with MRSA [9]. Thus, some healthy people get a swab taken of their skin or inside of their nose to see if they are carrying MRSA, which, as you recall, is harmless on the skin [9]. If so, an antibiotic cream applied can reduce the chance of the bacteria entering the body through an open wound and spreading MRSA to other people who are susceptible to it [9].

Is there anything people can do to help combat this issue?

To help prevent this potential catastrophe, the following preventative measures need to be taken:

First, it is important that medical professionals try to put a halt to prescribing antibiotics for viral infections [9]. As you may recall, antibiotics have absolutely no effect on viruses, such as the common cold. At one time, antibiotics were administered to help prevent a ‘secondary infection’ with bacteria, which also increases the development of resistance [9]. A secondary infection is one in which a bacterium takes advantage of an already ill host to invade.

Secondly, in the instance that individuals do acquire bacterial infections, having them finish their entire dose of antibiotics, whether or not they feel better early, is critical [9]. Doing so stops resistant bacteria in their tracks from surviving and multiplying [9]. Like bouncers at a night club, finishing one’s antibiotic dose takes care of those last tough stragglers, until the party’s over.

And thirdly, measures to control infections in hospitals include frequent hand washing (especially of healthcare staff between patients) [9]. This has been proven to drastically decrease or stop the chances of any particular resistant bacterium infecting multiple patients [9].

Why can’t we just make more antibiotics?

This certainly seems like an obvious question, however, researching and developing new drugs is not only very difficult and expensive (the cost to bring a drug from initial research to the public is about $900 million US), but also there is often little guarantee that these funds can be recovered through sales of the drug, due to the unpredictable risk of an antibiotic becoming completely resisted by bacteria and thus potentially useless [12]. In addition, there are only so many types of antibiotics; as the years progress, it is becoming increasingly difficult to find completely new ways in which they can be effective [12].

money

Unsurprisingly as a result, experimental undertaking into developing new antibiotics has more than halved in the past ten years alone 12. Pharmaceutical companies prefer to instead focus their efforts on drugs that have more ‘public appeal’, and thus guaranteed profit [12].
Citations & Literature

1. Canadian Committee on Antibiotic Resistance, About CCAR. 2009. Obtained from: http://www.ccar-ccra.com/english/home-e.shtml (accessed March 29, 2009).

2. CHICA-Canada (Community & Hospital Infection Control Association- Canada). 2008. Antibiotic Resistant Organisms. Obtained from: http://www.chica.org/links_aro.html (Accessed March 30, 2009).

3. CHICA-Canada (Community & Hospital Infection Control Association- Canada). 2009. News Headlines & Mission. Obtained from: http://www.chica.org/ (Accessed March 30, 2009).

4. Dubnau, D. DNA uptake in bacteria. 1999. Annu Rev Microbiol. 53, 217-44. Obtained from: http://www.ncbi.nlm.nih.gov/pubmed/10547691 (Accessed March 30, 2009).

5. Horton, H.R., Moran, L.A., Scrimgeour, K.G., Perry, M.D., Rawn, J.D. 2006. Principles of Biochemistry, 4th Edition. Pearson Education, Inc. Upper Saddle River, New Jersey.

6. Wikipedia, Antibiotic Resistance. 2009. Obtained from: http://en.wikipedia.org/wiki/Antibiotic_resistance (accessed March 25, 2009).

7. Kothari, A. and Sagar, V. 2008. J Infect Developing Countries 2(5): 354-358. Obtained from: http://jidc.org/issn1972-2680/current-issue/185-antibiotic-resistance-in-pathogens-causing-community-acquired-urinary-tract-infections-in-india-a-multicenter-study (accessed March 29, 2009).

8. Mayo Foundation for Medical Education and Research, Mayo Clinic: MRSA Infection. 2008. Obtained from: http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=symptoms (accessed March 29, 2009).

9. Medical News Today- MRSA & Drug Resistance. 2009. MediLexicon International Ltd. Obtained from: http://www.medicalnewstoday.com/articles/10634.php (accessed March 27, 2009).

10. Raghunath D. 2008. Emerging antibiotic resistance in bacteria with special reference to India; J. Biosci. 33, 593–603. Obtained from: http://www.ias.ac.in/jbiosci/nov2008/593.pdf (Accessed March 30, 2009).

11. Salyers, A. A. and Whitt, D.D. 2005 Revenge of the Microbes: How Bacterial Resistance Is Undermining the Antibiotic Miracle. ASM Press, American Society for Microbiology, Washington DC.

12. Shetty, P. Science and Development Network, Antibiotic Resistance. 2008. Obtained from: http://www.scidev.net/en/health/antibiotic-resistance/features/antibiotic-resistance-frequently-asked-questions.html (accessed March 29, 2009)

13. The World Health Report 2008, Primary Health Care – Now More Than Ever (World Health Organization. Obtained from: http://www.who.int/whr/2008/en/index.html (Accessed March 30, 2009).

14. The U.S. Department of Health and Human Services. 1995. The Rise of Antibiotic-Resistant Infections. Obtained from: http://www.questia.com/googleScholar.qst?docId=5002239353 (Accessed March 30, 2009).

15. Wikipedia, Bacterial Conjugation. 2009. Obtained from: http://en.wikipedia.org/wiki/Bacterial_conjugation (Accessed March 30, 2009).

16. Wikipedia, Transformation. 2009. Obtained from: http://en.wikipedia.org/wiki/Transformation_(genetics) (Accessed March 30, 2009).

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