wk 5- antimicrobial stewardship Flashcards
antimicrobial resistance what is it?
Antimicrobial resistance arises via random mutations BUT is also a consequence of, and accelerated by antimicrobial overuse, underuse and misuse.
how do agents become resistant to antimicrobials? 3
Genetic material (DNA), which codes for resistance traits can be exchanged between microbial cells via:
Transformation: uptake of free DNA from lysed microbial cells in the environment into the genome of living cells.
Conjugation: horizontal gene transfer involving direct cell to cell contact to facilitate transfer of plasmids from donor to recipient cells.
Transduction: injection of viral genetic material into bacterial cells via bacteriophage
how do agents become resistant to antimicrobials?
Genetic material (DNA), which codes for resistance traits can be exchanged between microbial cells via:
Transformation: uptake of free DNA from lysed microbial cells in the environment into the genome of living cells.
Conjugation: horizontal gene transfer involving direct cell to cell contact to facilitate transfer of plasmids from donor to recipient cells.
Transduction: injection of viral genetic material into bacterial cells via bacteriophage
what is antimicrobial stewardship
safe and effective prescription and use of antimicrobial agents to improve patient outcomes, reduce adverse sequelae of antimicrobial use including antimicrobial resistance, and ensure cost-effective therapy
MINDME antimicrobial creed
M- microbiology samples collected for identification and antimicrobial susceptibility testing
I- indications should be evidence based with improved patient prognosis
N- narrow spectrum required. reduces collateral damage and suboptimal exposure to antimicrobials.
D- dosage appropriate to type and site of infection
M- minimise duration of therapy 5-7 days and not exceeding unless theres proof short duration isn’t adequate.
E- ensure monotheraphy in most cases. synergy of drugs is useful in treatment of multiple drug resistant infectious agents and extending spectrum of treatment of poly microbial infections.
risks of drug delivery 2
- route of administration affects the risk associated with portals of entry in the chain of infection
- also risks associated with distribution of the drug (restrict so endogenous microbiota isn’t destroyed and opportunistic resistant populations aren’t created
drug selection is importance because
- narrow spectrum agents restrict the effect of exposure to the targeted infectious agent. it reduces the development of antimicrobial resistance and collateral damage of endogenous microbiota.
importance of drug metabolism
drug must be able to reach the affected area at a therapeutic level. examples are neurological infections with the blood brain barrier restricting access and metabolism of liver before arrival at site.
types of antimicrobial agents 3
- Drugs that inhibit the growth/replication of infectious agents (for example, bacteriostatic)
-Drugs that kill the infectious agent (for example, bacteriocidal)
-Drugs that lyse the infectious agent cells (for example, bacteriolytic)
what do antimicrobials target?
cellular structures and or functions in infectious agents
how can u reduce antimicrobial resistance? 2
-limiting exposure to antimicrobials
which reduces the selective pressure applied to infectious agents and the horizontal transfer of genetic information between cells of infectious agents.
-knowing the resistance profiles of circulating pathogens in population groups
the correct and effective antimicrobial agent can be chosen for first-line treatment. This reduces exposure of the pathogen and opportunists to sub-optimal doses of antimicrobial agents known to accelerate the development of resistance.
how to reduce antimicrobial resistance occurring? 4
-infection prevention and control (precautions in place)
-antimicrobial stewardship (prescription, restriction and administration reduces selective pressure)
-surveillance of resistance profiles
-drug development
therapeutic use of antimicrobials, when and who shouldn’t use them 4
Antimicrobial selection is complicated by factors associated with susceptible hosts. The optimal treatment options should be determined by evaluation of the patient’s clinical history, the identity of the infectious agent, and the results of antimicrobial susceptibility testing.
age- young and elderly susceptible to increased drug toxicity mostly elderly bc of poor renal function.
comorbidities- altered host physiology and medication interaction
pregnancy/breastfeeding- mode of action interferes with essential developmental processes
poly pharmacy- drug-drug interactions and adverse outcomes
empirical therapy is?
educated guess
drug targets for bacterial infections 4
- inhibition of cell wall synthesis- bactericidal and inhibit the formation of a rigid cell wall (include b-lactams and glycopeptides such as pennicillins)
- disruption of the cell membrane - bactericidal agents that increase the permeability of the cell membrane( membrane lysis)
- inhibition of protein synthesis- bacteriostatic that target ribosomal subunits
- inhibition of nucleic acid synthesis - inhibition of DNA gyrase that unwinds and supercoils DNA, also RNA polymerase and transcription and replication of binding of drug metabolites to DNA, these all inhibitions considered bactericidal and the interference with the metabolic pathway of folic acid being bacteriostatic
