BIOL1121 UNIT7 Discussion : Antibiotic Resistance

 

1. Write a sentence for each of these mechanisms of horizontal gene transfer in bacteria, describing the manner in which the DNA can be transferred from one cell to another.

Transduction refers to the transfer of DNA from one cell to another by a virus, and DNA is the transforming principle (Clark, Choi & Douglas, 2020). Those viruses are called bacteriophages, and those are "bacterial viruses that invade bacterial cells and, in the case of lytic phages, disrupt bacterial metabolism and cause the bacterium to lyse" (Sulakvelidze, Alavidze & Morris, 2001, para.3). Chase and Hershey found that the bacteriophage infects the host bacterial cell by attaching to its surface, and then it injects its nucleic acids inside the cell; the phage DNA makes multiple copies of itself using the host machinery, and eventually bursts the host cell (Clark, Choi & Douglas, 2020). DNA can be transferred from one cell to another in this way.


2. Choose a disease or an organism that has a well-documented mechanism of resistance (such as methicillin resistant Staphylococcus aureus - MRSA or tuberculosis) and see if you can identify the gene or genes that confer resistance and the method of DNA transfer thought to contribute to its spread. 

 "Pathogenic E. coli are typically passed to humans from ruminant animals (cows or sheep) via fecal contamination in the food chain or through consumption of raw milk or meat products" (Turner, 2011, para.3). For example, strain O104:H4 makes Shiga toxin which has phage genes being expressed by infected bacteria, and when an E. coli bacterium gets infected with a Shiga-toxin-producing phage, it infects humans (Turner, 2011). O104: H4 is known to carry the bla TEM-1 and bla CTX-M-15 genes, which are extended-spectrum β-lactamase producing bacteria, and those confer resistance (National Institute of Infectious Diseases., 2012).


3. Finally, discuss the danger that antibiotic resistance poses in today's society. Consider how man has contributed to this and suggest any strategies that you think may be able to halt it or prevent its expansion.

Turner explains that when bacteria are exposed to some types of antibiotics, they undergo what is called the SOS response, which induces the phage to start replicating, and active replication of the phage causes the bacterial cells to burst open, which releases the phage more (2011). Antibiotics can create more unusual and dangerous strains in today's society in this way. Acheson found Shiga-toxin-producing phage transfer between E. coli in response caused by antibiotic and said, "The potential for the creation of new pathogens via phage release is absolutely a factor in the broader environmental danger of overuse of antibiotics" (Turner, 2011).

To prevent the spread of antibiotic resistance, it is important to reduce the risks that we individuals have an infection to viruses and need antibiotics, and prevent the spread of the infection. At the same time, medicians also should not prescribe antibiotics that patients do not need.

 

References 

Clark, M.A., Choi, J. & Douglas, M. (2020). Biology 2e. Open Stax. Retrieved from https://openstax.org/books/biology-2e/pages/preface 

National Institute of Infectious Diseases. (2012). IASR 33 (1), 2012 [Special feature related information] Cases of symptomatic complaints caused by intestinal agglutinating Escherichia coli O126: H27-Hamamatsu City. Retrieved from https://www.niid.go.jp/niid/ja/component/content/article.html?id=968:dj38344

Sulakvelidze, A., Alavidze, Z., & Morris Jr, J. G. (2001). Bacteriophage therapy. Antimicrobial agents and chemotherapy, 45(3), 649-659. 
 Retrieved from https://journals.asm.org/doi/full/10.1128/AAC.45.3.649-659.2001

Turner, M. (2011). Phage on the rampage. Retrieved from https://www.nature.com/articles/news.2011.360