Teixobactin: Difference between revisions
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==Mechanism of Action, Efficacy, and Resistance of Teixobactin== | ==Mechanism of Action, Efficacy, and Resistance of Teixobactin== | ||
[[Image:TeixobactinMIC.png|thumb|450px|right|A comparison of Teixobactin's activity against gram negative and gram positive bacteria using the MIC data determined by | [[Image:TeixobactinMIC.png|thumb|450px|right|A comparison of Teixobactin's activity against gram negative and gram positive bacteria using the MIC data determined by Ling <i>et al</i> via [http://en.wikipedia.org/wiki/Broth_microdilution broth microdilution].[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] Image created by Lisette Espinosa. | ||
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[http://en.wikipedia.org/wiki/Minimum_inhibitory_concentration Minimum inhibitory concentrations] (MIC) were used to measure the effectiveness of teixobactin against pathogenic bacteria.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] While teixobactin was not effective against gram-negative bacteria, less than 0.6 μg/mL of the drug was necessary to visibly inhibit the growth of many gram positive bacteria tested including pathogenic MRSA, VRE, Bacillus anthracis, and Clostridium difficile.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] No toxicity toward mammalian cells was found as expected from the [http://en.wikipedia.org/wiki/Mechanism_of_action mechanism of action] . The antibiotic works through inhibiting cell wall synthesis by binding to two cell wall precursors, lipid II and lipid III.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] Though researchers looked for possible teixobactin-resistant mutants using S. aureau and M. tuberculosis through plating the bacteria in media with four times their respective MICs, no resistant mutants were found.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] Studies done in the past on vancomycin, another antibiotic that binds to lipid cell wall precursors, suggest that teixobactin's lack of development of resistance may be due to the fact that the lipids are made from organic precursors. | [http://en.wikipedia.org/wiki/Minimum_inhibitory_concentration Minimum inhibitory concentrations] (MIC) were used to measure the effectiveness of teixobactin against pathogenic bacteria.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] While teixobactin was not effective against gram-negative bacteria, less than 0.6 μg/mL of the drug was necessary to visibly inhibit the growth of many gram positive bacteria tested including pathogenic MRSA, VRE, Bacillus anthracis, and Clostridium difficile.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] No toxicity toward mammalian cells was found as expected from the [http://en.wikipedia.org/wiki/Mechanism_of_action mechanism of action] . The antibiotic works through inhibiting cell wall synthesis by binding to two cell wall precursors, lipid II and lipid III.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] Though researchers looked for possible teixobactin-resistant mutants using S. aureau and M. tuberculosis through plating the bacteria in media with four times their respective MICs, no resistant mutants were found.[http://www.nature.com/nature/journal/v517/n7535/full/nature14098.html <sup>1</sup>] Studies done in the past on vancomycin, another antibiotic that binds to lipid cell wall precursors, suggest that teixobactin's lack of development of resistance may be due to the fact that the lipids are made from organic precursors rather than synthesized [http://en.wikipedia.org/wiki/De_novo de novo] from DNA like proteins, making development of resistance through mutation alone more difficult.[http://www.nature.com/nature/journal/v517/n7535/full/nature14193.html <sup>3</sup>] This | ||
Revision as of 04:33, 24 March 2015
The development of new antibiotics has been a difficult task due to the rapid evolution of resistant bacteria. Teixobactin is a newly discovered antibiotic that is effective against gram positive bacteria including antibiotic-resistant strains, such as methicilin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), without evidence of resistance development.1 The antibiotic, isolated from the soil using a device called the iChip, works by inhibiting cell wall synthesis.1
Introduction
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Legend/credit: Electron micrograph of the Ebola Zaire virus. This was the first photo ever taken of the virus, on 10/13/1976. By Dr. F.A. Murphy, now at U.C. Davis, then at the CDC.
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Identification
Teixobactin was isolated from a new species, Eleftheria terrae, from soil using a high-throughput device called the iChip.1 The iChip is used to isolate previously unculturable bacteria by growing microbes in situ where their normal environmental factors are used to cultivate the bacteria in hundreds of miniature diffusible chambers on the iChip.2 Compared to standard Petri dishes, the colony count for soil bacteria using the iChip was 5 times higher when cultivating from a single colony's worth of bacteria.2 Extracts from thousands of isolates were tested for antibiotic activity, and the discovery of teixobactin's properties lead to the identification and classification of E. terrae using 16S rRNA gene sequencing.1 Relatives of E. terrae were not previously known to produce antibiotics.1
Mechanism of Action, Efficacy, and Resistance of Teixobactin
Minimum inhibitory concentrations (MIC) were used to measure the effectiveness of teixobactin against pathogenic bacteria.1 While teixobactin was not effective against gram-negative bacteria, less than 0.6 μg/mL of the drug was necessary to visibly inhibit the growth of many gram positive bacteria tested including pathogenic MRSA, VRE, Bacillus anthracis, and Clostridium difficile.1 No toxicity toward mammalian cells was found as expected from the mechanism of action . The antibiotic works through inhibiting cell wall synthesis by binding to two cell wall precursors, lipid II and lipid III.1 Though researchers looked for possible teixobactin-resistant mutants using S. aureau and M. tuberculosis through plating the bacteria in media with four times their respective MICs, no resistant mutants were found.1 Studies done in the past on vancomycin, another antibiotic that binds to lipid cell wall precursors, suggest that teixobactin's lack of development of resistance may be due to the fact that the lipids are made from organic precursors rather than synthesized de novo from DNA like proteins, making development of resistance through mutation alone more difficult.3 This
Limitations of Teixobactin
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Further Reading
[Sample link] Ebola Hemorrhagic Fever—Centers for Disease Control and Prevention, Special Pathogens Branch
References
Edited by (your name here), a student of Nora Sullivan in BIOL168L (Microbiology) in The Keck Science Department of the Claremont Colleges Spring 2014.