INTRODUCTION
Hi, my name is Becky. I am an Alverno College nursing student enrolled in a Microbiology class. We were assigned a topic and have to write and publish a blog about that. My topic given was antibiotic resistance. Antibiotic resistance is an issue that concerns citizens in all nations of the world. Antibiotic resistance interests me because the microorganisms ability to evolve and become unaffected by drugs and chemicals will affect my career and knowledge as a nurse when trying to care for patients with the best possible treatment. This blog will cover background and why this is a public health issue, mechanisms that create antibiotic resistance, and how to treat a microorganism after it becomes resistance. Examples, pictures, and stories from social media sites are also included to give a real world view on the issue.
BACKGROUND
For a microorganisms to become antibiotic resistant, they have to be introduced to antibiotics. Antibiotics are medications, grown from various other microorganisms and fungi, that inhibit the growth or destroy the infectious microorganism (APA, 2014). Antibiotic resistance is when a microorganism is able to withstand and be unaffected the antibiotics (APA, 2014). The concern that many people have when an infectious microbe becomes antibiotic resistant is that the resistant strain is what will now be spreading throughout a population. When the resistant strain is affecting enough people, it has the capacity to kill large amounts of citizens, and since it would be antibiotic resistant, there would be no way to treat it with the conventional methods. The first recorded case of an antibiotic resistant infection was due to an enzyme produced to counteract penicillin (Guilfoile, 2007).
PUBLIC HEALTH CONCERN
An issue in the spread of antibiotic resistant illnesses are that in some countries, antibiotics are sold as over the counter drugs, meaning they do not require a prescription. Typically, theses drugs are not the same dosage os prescribed medications. This increases the likelihood that a microbe may become antibiotic resistant because, with the lower dosage of the antibiotic, the drug or chemical that inactivates the infectious microbe is able to enter the cell, but it is not enough to fully kill the microbial cell. Now, the microbe has the knowledge of the antibiotics that are used to inactive it, but since it was not completely inactivated, it has the opportunity to alter what is being targeted or the way that the antibiotic is enter the cell, so that in the future, other strains being targeted by the antibiotic will not be affected and can continue to survive in the host.
Once a microbe has become antibiotic resistant, the products of divisions and reproduction will also be resistant. Also, the resistant strain is what will be transferred and spread to other hosts, whether human or non-human. This can make containing the newly resistant strain difficult to contain.
Another reason that antibiotic resistance is spreading, is the misuse of antibiotics to treat viral infections. Because of the make-up and structure of viruses, they are not affected by antibiotics (Tortora, 2013). When an individual takes antibiotics to treat a viral infection, they are introducing the antibiotic to their body, and bacterial microbes can still gain resistance, even if it is not what is causing that host to feel ill. Another misuse of antibiotics is not completing a full course of treatment. Even is a person is beginning to feel better, they should finish all prescribed medications (FDA, 2014). The host may feel better but that does not mean that the infectious microbe has been totally inactivated. If it has not been, then it could still develop resistance and spread.
HOW DOES IT HAPPEN?
There are three processes that a microbe can go through to become antibiotic resistant (Dever & Dermody, 1991).
- Enzyme degradation
This is where either an enzyme is naturally present, or the cell will produce it in response to the antibiotic (Toder, 2011). When the enzyme comes in contact with the antibiotic, the enzyme has the ability to inactive and denature the antibiotic (Toder, 2011).
2.Targeted proteins altered
2.Targeted proteins altered
When a microbe is being affected by an antibiotic, it is typically because the microbes proteins are being targeted. Once the proteins of the cell are denatured, the microbes would not have the ability to infect any further. Over time, some microbes have the ability to change those protein, either slightly or all together (Toder, 2011). Once those proteins are altered, the drug or chemical meant to denature them, will no longer have an affect on them.
3.Changes to the outer membrane
3.Changes to the outer membrane
This can happen in two ways. 1) alteration to how permeable the membrane is or 2) changes in the efflux passages (Toder, 2011). When a change in the permeability of the outer membrane occurs, the antibiotic would not be able to enter the cell at all or very little would be able to enter the cell. Some cells, such as Gram negative and cells that contain mycolic acid are naturally occurring outer membranes impermeable to drugs and chemicals. The efflux pump is a transport passage in the outer membrane that allows things to either enter or leave the cell. When antibiotics enter the cell, the efflux pump may gain the ability to expel the antibiotics from the cell before it has the chance to denature the proteins or targeted mechanisms (Toder, 2011).
An example of resistance is B-Lactam (Towner, 1996). B-Lactam is a category for penicillin medications. When a microbe becomes resistant to B-Lactam, the B-Lactam ring in the antibiotic, which makes it affective to the infecting microbe, is hydrolyzed by the enzyme B-Lactamase (Bachman, Li & Townsend, 1998). This renders the antibiotic inactive because the B-Lactam is unable to attach to the microbe and inactive that cell. This is a common example for the mechanism of enzyme degradation.
There are two changes that a microbe can go through for it to become resistant to antibiotics (Toder, 2011).
- Natural resistance
This is when the microbe naturally has what it needs to become resistance to chemicals and drugs. The microbes may naturally lack the proper transport passage, have an outer membrane impermeable to chemicals or drugs, lack the targeted protein, or contain the enzyme to inactivate the antibiotic (Toder, 2011).
2.Acquired resistance
2.Acquired resistance
This is when the microbe will evolve itself to become resistant to the drugs and chemicals. The DNA can change or the microbe can transfer DNA with another microbe to alter DNA (Toder, 2011). When the DNA is altered, several aspects of the cell may also be altered as well. This includes the enzymes, proteins, and outer membrane characteristics. There are two spontaneous ways that DNA can be transferred from one microbe to another.
1) Vertical Gene Transfer- this is when about every 10-8 or 10-9 will develop the resistance within the strain (Toder, 2011). An example of this is E. Coli. Once the DNA in one microbe has been successfully altered, they are transferred to other infectious microbes during the DNA replication stage (Toder, 2011). Although it is rare, once this type of resistance occurs, it spreads very quickly throughout the majority population of the microbe (Toder, 2011).
2) Horizontal Gene Transfer- this is where the resistant DNA is contained in small pockets and can be transferred between individual cells of the same species or of other species of microbes (Toder, 2011). This process can take place in three different way. The first is through conjugation, direct cell to cell contact (Toder, 2011). The second is transformation, when the DNA is taken up from the environment (Toder, 2011). The third is transduction, when bacteria-specific viruses transfer DNA very closely (Toder, 2011).
(Tudor, 2011)
(Tudor, 2011)
HOW CAN WE TELL?
There are several tests that can be used to determine if a strain of a bacteria has become antibiotic resistant or if it is on its way to becoming antibiotic resistant.
1. Dilution Method- here the bacteria is grown in a broth. The sensitivity is based on the amount of growth within that broth.
2. Disc Diffusion Method- the bacteria is spread over the whole of a nutrient agar, antibiotic discs are stamped onto the disc. After an inoculation period, the amount of space around the certain antibiotic is measured. The larger the circle around the disc, the more sensitive the antibiotic.
3. The E-Test Method- a plastic strip with the antibiotic are varying amounts, gradually decreasing down the strip is inoculated with bacteria. Where there is the most amount of growth, the bacteria is least sensitive.
(Bauer, 2000)
TREATMENT
Once an infectious microbe has become antibiotic resistant, the typical way of treatment will no longer work. Options for treatment become very limited. There are other options of treat of an individual that is infected with a resistant strain. One of the possibilities is known as multi-drug therapy (MDT). This is the treatment of using multiple drugs (two or more), typically each affect the cell in a different way, in the hopes that the combination will inactive the infectious microbe (Davies & Davies, 2010). One weakness of using multi drug therapy is that it encourages that microbe to become multi drug resistant, when the strain is resistant to one or more antibiotic. Most notably, this has happened to a strain of Tuberculosis. Following, is an article about the life an individual and how they had to live once he had contracted a strain of TB that was resistant to antibiotics.
SO, WHAT CAN I DO?
Everybody can help in the fight to limit infectious bacterial microbes that will become antibiotic resistant. There are very simple ways to reduce the chances of creating or contracting an antibiotic resistant strain (FDA, 2014).
- Do not self-medicate with past medications
- Take the whole treatment you are prescribed
- Do not skip doses
- Do not take medications prescribed to another person
- Wash your hands
- Talk you your health care professional
- Support scientific research
References
antibiotic. (n.d.). The American Heritage® New Dictionary of Cultural Literacy, Third Edition. Retrieved November 08, 2014, from Dictionary.com website: http://dictionary.reference.com/browse/antibiotic
Bachmann, B. O.; Li, R.; Townsend, C. A. (1998). "Β-Lactam synthetase: A new biosynthetic enzyme". Proceedings of the National Academy of Sciences of the United States of America 95 (16): 9082–9086. doi:10.1073/pnas.95.16.9082. PMC 21295. PMID 9689037
Bauer, K. (2000). Kirby bauer disk diffusion susceptibility test protocol. Retrieved from: https://mayapedia.me/posts/kirby-bauer-disk-diffusion-susceptibility-test-protocol/
Dever, L. & Dermody, T (1991). Mechanisms of bacterial resistance to antibiotics. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/2025137
FDA, (2014). Combating antibiotic resistance. Retrieved from: http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm092810.htm
Michigan State (2011). Examples of antibiotic sensitivity testing methods. Retrieved from: http://amrls.cvm.msu.edu/microbiology/detecting-antimicrobial-resistance/test-methods/examples-of-antibiotic-sensitivity-tesing-methods
Toder, K (2011). Bacterial resistance of antibiotics. Retrieved from: http://textbookofbacteriology.net/resantimicrobial_3.html
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