On page 117, Staph bacteria evolve due to increasing antibiotics. Staph bacteria have evolved from being penicillin resistant to even vancomycin resistant. They have evolved to have a selective advantage over other staph bacteria which allows them to survive and reproduce. This relates to big idea 1 which states how evolution drives the diversity and unity of life.
Explain how staph based infections develop and the method through which genetic variation can arise in staph bacteria. Also, research how penicillin was an effective antibiotic in response to staph bacteria but now isn't.
(Andrew Arceo - aarceo4@students.d125.org)
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ReplyDeleteIn 1928, Alexander Fleming discovered penicillin that habited the growth of staph. In 1942, when penicillin was first used to treat infections in humans, there was not any report of penicillin-resistant staph. However, in 1950, 40 percent of all staph infections were penicillin-resistant; in 1960, 80 percent of all staph infections were penicillin-resistant. This was an indication of staphylococcus aureus evolved. Methicillin, a specialized relative of penicillin, was introduced in 1959; MRSA, the first incident of methicillin-resistant staph, was reported in 1961, and MRSA is currently entrenched in hospitals. After methicillin, vancomycin, a different class of antibiotics, is used in these days to treat Staph infections. However, in 1996, VRSA, vancomycin-resistant staph, was reported (Moalem 117). “The development of antibiotic resistance by the bacterium is ominous.” The antibiotic resistance of the bacterium is related to Big Idea 1(The process of evolution drives the diversity and unity of life). By 2007, diseases, caused by Staph, that are almost completely resistant to antibiotics are becoming much more common. To protect hospitalized patients, it is critical to quickly discover new antibiotics that Staph is not resistant to. Furthermore, more than 500,000 people are hospitalized with Staph infections every year (http://go.galegroup.com/ps/retrieve.do?sgHitCountType=None&sort=RELEVANCE&inPS=true&prodId=GPS&userGroupName=astevenson&tabID=T001&searchId=R3&resultListType=RESULT_LIST&contentSegment=&searchType=BasicSearchForm¤tPosition=1&contentSet=GALE%7CCX3045200225&&docId=GALE|CX3045200225&docType=GALE&role=GVRL). The genetic variation of staph bacteria is oner of bacterial transformations: bacteria have the ability to transform harmless cells into virulent ones by transferring some genetic factor from one bacterial cell to another (Griffith performed experiments with several different strains of the bacterium Diplococcus pneumoniae. DNA, not protein, is the genetic material that is the transformation factor. Avery, MacLeod, and McCarty proved that DNA was the agent that carried the genetic characteristics form the virulent dead bacteria to the living nonviolent bacteria through their experiment in 1944. In addition, related to what we have learned in class, the antibiotic resistance of the bacterium has followed the principles of natural selection. Bacteria’s population tends to grow exponentially, and there were genetic variations over time among bacteria that help individuals survive and reproduce. Eventually, the advantageous traits were accumulated in a population of Staph: the first appearance of VRSA was in Japan.
ReplyDelete(Fabiola Yun, jooyun4@students.d125.org)