Acquired resistance - Revision history

Bosmana fem: /* FEM PAGE CONTRIBUTORS */

2023-04-10T22:02:30Z

FEM PAGE CONTRIBUTORS

← Older revision		Revision as of 22:02, 10 April 2023
Line 28:		Line 28:
	* Courvalin P. 1996. The garrod Lecture: Evasion of Antibiotic Action by Bacteria. Journal of Antimicrobial Chemotherapy. 37:855-869		* Courvalin P. 1996. The garrod Lecture: Evasion of Antibiotic Action by Bacteria. Journal of Antimicrobial Chemotherapy. 37:855-869

	==FEM PAGE CONTRIBUTORS==		<div style="display: inline-block; width: 25%; vertical-align: top; border: 1px solid #000; background-color: #d7effc; padding: 10px; margin: 5px;">
	* Vladimir Prikazsky		'''FEM PAGE CONTRIBUTORS 2007'''
	* luca		:Vladimir Prikazsky
			:luca
			</div>
	[[Category:Main pathogens and resistance]]		[[Category:Main pathogens and resistance]]

Bosmana fem at 14:19, 23 March 2023

2023-03-23T14:19:50Z

← Older revision		Revision as of 14:19, 23 March 2023
Line 19:		Line 19:
	* by inactivation of antimicrobial agents via modification or degradation		* by inactivation of antimicrobial agents via modification or degradation
	* by modification of the antimicrobial target within the bacteria		* by modification of the antimicrobial target within the bacteria


	____		____

Line 29:		Line 27:
	* McManus MC. Mechanisms of bacterial resistance to antimicrobial agents.Am J Health Syst Pharm. 1997;54:1420 –1433		* McManus MC. Mechanisms of bacterial resistance to antimicrobial agents.Am J Health Syst Pharm. 1997;54:1420 –1433
	* Courvalin P. 1996. The garrod Lecture: Evasion of Antibiotic Action by Bacteria. Journal of Antimicrobial Chemotherapy. 37:855-869		* Courvalin P. 1996. The garrod Lecture: Evasion of Antibiotic Action by Bacteria. Journal of Antimicrobial Chemotherapy. 37:855-869

			==FEM PAGE CONTRIBUTORS==
			* Vladimir Prikazsky
			* luca

	[[Category:Main pathogens and resistance]]		[[Category:Main pathogens and resistance]]

Bosmana fem at 14:06, 23 March 2023

2023-03-23T14:06:35Z

← Older revision		Revision as of 14:06, 23 March 2023
Line 1:		Line 1:
			Acquired resistance occurs when a particular microorganism obtains the ability to resist the activity of an antimicrobial agent to which it was previously susceptible. This can result from the mutation of genes involved in normal physiological processes and cellular structures, from the acquisition of foreign resistance genes or from a combination of these two mechanisms.

			Unlike intrinsic resistance, traits associated with acquired resistance are found only in some strains or subpopulations of each particular bacterial species. Acquired resistance results from successful gene change and/or exchange involving mutation or horizontal gene transfer via transformation, transduction or conjugation.

			==Vertical gene transfer==
			A mutation is a spontaneous change in the DNA sequence within the gene that may lead to a change in the trait which it codes for. Any change in a single base pair may lead to a corresponding change in one or more of the amino acids for which it codes, which can then change the enzyme or cell structure, consequently changing the affinity or effective activity of the targeted antimicrobials.
			In prokaryotic genomes, mutations frequently occur due to base changes caused by exogenous agents, DNA polymerase errors, deletions, insertions and duplications. For prokaryotes, there is a constant rate of spontaneous mutation of about 0.0033 mutations per DNA replication that is relatively uniform for a diverse spectrum of organisms. The mutation rate for individual genes varies significantly among and within the gene.

			==Horizontal gene transfer==
			Many of the antibiotic resistance genes are carried on plasmids, transposons or integrons that can act as vectors that transfer these genes to other members of the same bacterial species, as well l as to bacteria in another genus or species.

			* Conjugation occurs when there is direct cell-cell contact between two bacteria (which need not be closely related) and transfer of small pieces of DNA called plasmids takes place. This is thought to be the main mechanism of HGT.
			* Transformation is a process where parts of DNA are taken up by the bacteria from the external environment. This DNA is normally present in the external environment due to the death and lysis of another bacterium.
			* Transduction occurs when bacteria-specific viruses (bacteriophages) transfer DNA between two closely related bacteria.
			These genetic mechanisms give to the bacteria some functional capacities that permit them to survive, the main ones are:

			* by prevention of the antimicrobial from reaching its target by reducing its ability to penetrate into the cell
			* by expulsion of the antimicrobial agents from the cell via general or specific efflux pumps
			* by inactivation of antimicrobial agents via modification or degradation
			* by modification of the antimicrobial target within the bacteria


			____

			Link to European IC/HH Core Competencies: Area 4. Infection control activities

			=References:=
			* Tenover FC. Mechanisms of antimicrobial resistance in bacteria. Am J Med. 2006;119(6 Suppl 1):S3-S10.
			* McManus MC. Mechanisms of bacterial resistance to antimicrobial agents.Am J Health Syst Pharm. 1997;54:1420 –1433
			* Courvalin P. 1996. The garrod Lecture: Evasion of Antibiotic Action by Bacteria. Journal of Antimicrobial Chemotherapy. 37:855-869

	[[Category:Main pathogens and resistance]]		[[Category:Main pathogens and resistance]]

Bosmana fem: Created page with " Category:Main pathogens and resistance"

2023-03-23T12:23:42Z

Created page with " Category:Main pathogens and resistance"

New page

[[Category:Main pathogens and resistance]]