Antibiotics: Difference between revisions
No edit summary |
Cleaned up the text. |
||
| Line 1: | Line 1: | ||
Antibiotics are drugs which are used to treat infections. When they were first discovered they were thought to be a wonder drug that would eliminate all worldwide [[Infection|infection]]. However, soon it was realised that the [[Bacteria|bacteria]] they were treating would develop resistance against them. This resistance can be either intrinsic or acquired resistance. Acquired resistance is when initially the antibiotics | Antibiotics are drugs which are used to treat infections. When they were first discovered they were thought to be a wonder drug that would eliminate all worldwide [[Infection|infection]]. However, soon it was realised that the [[Bacteria|bacteria]] they were treating would develop resistance against them. This resistance can be either intrinsic or acquired resistance. Acquired resistance is when initially the antibiotics are effective at treating the infection although over time the bacteria develop resistance<ref>H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.</ref>. Intrinsic resistance is when the bacteria never respond to the antibiotics they have always had resistance. In response to the increase in antibiotic resistance new drugs keep being synthesized in an attempt to find new cures – however, the amount of new effective antibiotics being found is rapidly decreasing<ref>Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.</ref><ref>H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.</ref>. | ||
It was [[Alexander Fleming|Alexander Fleming]] who discovered the first known antibiotics. This was in the 1920’s when he saw [[Staphylococci|Staphylococci]] being inhibited by [[Penicillin|Penicillin]]. However discovering how to extract the penicillin and use it effectively did not occur until the | It was [[Alexander Fleming|Alexander Fleming]] who discovered the first known antibiotics. This was in the 1920’s when he saw [[Staphylococci|Staphylococci]] being inhibited by [[Penicillin|Penicillin]]. However discovering how to extract the penicillin and use it effectively did not occur until the 1940s<ref>Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.</ref>. | ||
There are three different types of antibiotics; [[Bacterostatic|bacteriostatic]], [[Bactericidal|bactericidal]] and [[Bacteriolytic|bacteriolytic]]. Bactericidal antibiotics on the other hand kill all of the bacteria present, ridding the body of any present infection | There are three different types of antibiotics; [[Bacterostatic|bacteriostatic]], [[Bactericidal|bactericidal]] and [[Bacteriolytic|bacteriolytic]]. Bactericidal antibiotics, on the other hand, kill all of the bacteria present, ridding the body of any present infection<ref>Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.</ref><ref>H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.</ref>. If you were to plot this on a graph of log cell number vs time, the total number of cells would remain constant (dead cells count towards total cell number), but the number of viable cells would drop dramatically. Bacteriostatic antibiotics act by simply halting the growth and proliferation of bacterial cells, to give the body time to deal with the infection. On the same type of graph, both total cell count and viable cell count would remain the same. Bacteriolytic antibiotics act to lyse the bacteria, dramatically decreasing the total cell count and the viable cell count. Many common antibiotics such as [[Penicillin]] act in this way. Penicillin acts by irreversibly binding to and inhibiting the enzyme ([[Transpeptidase]]) that creates cross-links between the peptidoglycan in the cell wall. The cell wall is now not functional to protect the bacterial cell from [[Lysis]] via [[Osmotic action]]. Bacteriolytic antibiotics may not be favourable in bacteria that contain endotoxins which would release upon cell lysis as these can be very harmful to the body. | ||
Antibiotics are used to treat [[Bacteria|bacteria]] that cause [[Infection|infection]]. The first antibiotic to be discovered was penicillin and was founded by [[Alexander Flemming|Alexander Fleming]]. | Antibiotics are used to treat [[Bacteria|bacteria]] that cause [[Infection|infection]]. The first antibiotic to be discovered was penicillin and was founded by [[Alexander Flemming|Alexander Fleming]]. | ||
=== '''How was Penicillin | === '''How was Penicillin discovered?''' === | ||
Alexander Flemming discovered penicillin completely by accident. He was working with a strain of ''[[Staphylococcus|Staphylococcus]]'' [[Bacteria|bacteria]] and found that the | Alexander Flemming discovered penicillin completely by accident. He was working with a strain of ''[[Staphylococcus|Staphylococcus]]'' [[Bacteria|bacteria]] and found that the Petri dishes became infected with [[Fungi|fungi]]. However, there was a ring around each colony where the [[Bacteria|bacteria]] had died. Flemming did some research into the [[Fungi|fungi]] and found it came from the Penicillium genus which is how penicillin got its name<ref>Sadava et al. (2012). Life, the Science of Biology. 10th ed. Sunderland: Sinauer Associates Inc. 608</ref>. | ||
=== Why do antibiotics work? === | === Why do antibiotics work? === | ||
[[Bacteria|Bacteria]] and [[Eukaryotes|eukaryotes]] form two different kingdoms meaning that there are many differences | [[Bacteria|Bacteria]] and [[Eukaryotes|eukaryotes]] form two different kingdoms meaning that there are many differences between them. These differences can be exploited when trying to beat an [[Infection|infection]]. Drugs can directly inhibit a process in [[Bacteria|bacteria without]] causing any disruption to a similar process in the host [[Organism|organism]]. Many antibiotics target the cell wall biosynthesis as [[Eukaryotic cells|eukaryotic cells]] don’t have cell walls making it an easy target<ref>Alberts et al. (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. 1521-1522.</ref>. | ||
=== References === | === References === | ||
<references /><br> | <references /><br> | ||
Revision as of 12:14, 18 October 2018
Antibiotics are drugs which are used to treat infections. When they were first discovered they were thought to be a wonder drug that would eliminate all worldwide infection. However, soon it was realised that the bacteria they were treating would develop resistance against them. This resistance can be either intrinsic or acquired resistance. Acquired resistance is when initially the antibiotics are effective at treating the infection although over time the bacteria develop resistance[1]. Intrinsic resistance is when the bacteria never respond to the antibiotics they have always had resistance. In response to the increase in antibiotic resistance new drugs keep being synthesized in an attempt to find new cures – however, the amount of new effective antibiotics being found is rapidly decreasing[2][3].
It was Alexander Fleming who discovered the first known antibiotics. This was in the 1920’s when he saw Staphylococci being inhibited by Penicillin. However discovering how to extract the penicillin and use it effectively did not occur until the 1940s[4].
There are three different types of antibiotics; bacteriostatic, bactericidal and bacteriolytic. Bactericidal antibiotics, on the other hand, kill all of the bacteria present, ridding the body of any present infection[5][6]. If you were to plot this on a graph of log cell number vs time, the total number of cells would remain constant (dead cells count towards total cell number), but the number of viable cells would drop dramatically. Bacteriostatic antibiotics act by simply halting the growth and proliferation of bacterial cells, to give the body time to deal with the infection. On the same type of graph, both total cell count and viable cell count would remain the same. Bacteriolytic antibiotics act to lyse the bacteria, dramatically decreasing the total cell count and the viable cell count. Many common antibiotics such as Penicillin act in this way. Penicillin acts by irreversibly binding to and inhibiting the enzyme (Transpeptidase) that creates cross-links between the peptidoglycan in the cell wall. The cell wall is now not functional to protect the bacterial cell from Lysis via Osmotic action. Bacteriolytic antibiotics may not be favourable in bacteria that contain endotoxins which would release upon cell lysis as these can be very harmful to the body.
Antibiotics are used to treat bacteria that cause infection. The first antibiotic to be discovered was penicillin and was founded by Alexander Fleming.
How was Penicillin discovered?
Alexander Flemming discovered penicillin completely by accident. He was working with a strain of Staphylococcus bacteria and found that the Petri dishes became infected with fungi. However, there was a ring around each colony where the bacteria had died. Flemming did some research into the fungi and found it came from the Penicillium genus which is how penicillin got its name[7].
Why do antibiotics work?
Bacteria and eukaryotes form two different kingdoms meaning that there are many differences between them. These differences can be exploited when trying to beat an infection. Drugs can directly inhibit a process in bacteria without causing any disruption to a similar process in the host organism. Many antibiotics target the cell wall biosynthesis as eukaryotic cells don’t have cell walls making it an easy target[8].
References
- ↑ H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.
- ↑ Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.
- ↑ H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.
- ↑ Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.
- ↑ Yassin, Dawson (2007). Pharmacology. 3rd ed. China: Mosby. p201-210.
- ↑ H P Rang, M M Dale et al. (2007). Rang and Dale's Pharmacology. 7th ed. Spain: Elsevier. 609-37.
- ↑ Sadava et al. (2012). Life, the Science of Biology. 10th ed. Sunderland: Sinauer Associates Inc. 608
- ↑ Alberts et al. (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. 1521-1522.