Term
| ESKAPE - 6 families of bacteria that are developing resistance |
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Definition
| Escheria, Staph, Klebsiella, Acinetobacter, Pseudomonas, Enterobacter |
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Term
| Ways that bacteria can exchange genes (3) |
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Definition
| Transformation, Transduction, Conjugation |
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Term
| Antibiotic resistance mechanisms of bacteria (5) |
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Definition
| Block entry, block binding, replace target, destroy antibiotic, don't activate antibiotic |
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Term
| Resistance - formal definition |
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Definition
| Bacteria are not inhibited by clinically-achievable, "nontoxic" levels of the antibiotic |
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Term
| Transformation - general process |
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Definition
| Uptake of foreign bacterial DNA by a new bacteria. 1) Cell lyses, releasing DNA; 2) DNA is taken into new cell; 3) DNA is integrated & expressed |
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Term
| Transduction - bacteriophage example |
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Definition
| Acquisition of new DNA via a vector. Normally viruses replicate & take their own DNA, lyse cell, and leave; bacteriophages can take some BACTERIAL DNA when they leave, thus accomplishing GENE TRANSFER if they infect a different bacterial strain (and, this doesn't kill the new bacteria either) |
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Term
| Conjugation - general process |
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Definition
| Direct cell-cell transfer, via sex pili |
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Term
| Conjugative plasmid; definition |
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Definition
| Plasmids that encode for the ability to transfer from cell to cell. Normal plasmids have an origin site "ori"; conjugative plasmids have a 2nd origin site "oriT" for DNA Transfer Apparatus |
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Term
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Definition
| Able to replicate as independent DNA molecules from their own origins. Applies to both plasmids and chromosomes |
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Term
| Imported resistance (transformation, transduction, conjugation) vs Mutational resistance? |
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Definition
| Prob of mutational = 1/10^6; prob of imported = 1/(10^3-10^5), a 10-1000x increase |
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Term
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Definition
| Inherent property of an organism making it antibiotic-resistant. Fungi produce their own penicillin, but they don't make peptidoglycan anyway so they are intrinsically B-lactam resistant. Not clinically relevant, because bacteria can't pick up this mutation from fungi |
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Term
| Acquired (active) resistance |
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Definition
| Obtains the ability to resist something it previously was unable to. S. fradiae makes neomycin AND an enzyme that inactivates neomycin that enters. Clinically relevant, because these active abilities can also be acquired |
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Term
| Example of how E. coli has acquired neomycin resistance |
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Definition
| Similar aminoglycoside phosphotransferase sequence to S. fradiae, which is neomycin resistant - probably acquired the resistance from S. fradiae. Very unlikely that this is random |
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Term
| ID the mechanism and type of example: Altered porin doesn't let B-lactam in |
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Definition
| Blocking entry - mutational example |
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Term
| ID the mechanism and type of example: Protein in membrane which actively pumps out tetracycline |
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Definition
| Blocking entry - Imported example |
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Term
| ID the mechanism and type of example: 1) Gram negative outer membranes/porins don't let vancomycin in. 2) Aminoglycoside uptake requires aerobic metabolism |
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Definition
| Blocking entry - Intrinsic example |
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Term
| ID the mech and type: RpsL (ribosomal binding ptn) doesn't bind streptomycin |
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Definition
| Altering target - mutation |
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Term
| ID the mech and type: RNA pol subunit doesn't bind rifampicin |
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Definition
| Altering target - mutation |
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Term
| ID the mech and type: RNA CH3transferase methylates rRNA, so erythromycin can't bind |
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Definition
| Altering target - imported |
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Term
| ID the mech and type: pNAM-NAG which doesn't bind vancomycin |
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Definition
| Altering target - imported |
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Term
| ID the mech and type: Alternative enzyme resistant to sulfonamides |
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Definition
| Replace target - imported |
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Term
| ID the mech and type: Alternate DHFR resists trimethoprim |
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Definition
| Replace target - imported |
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Term
| ID the mech and type: B-lactamases, aminoglycoside-inactivating enzymes |
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Definition
| Hydrolyzing/modifying antibiotic - imported |
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Term
| ID the mech and type: KatG that doesn't activate Isoniazid prodrug |
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Definition
| Failure to activate antibiotic - mutation? |
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Term
| Multigene resistance mechanism (vancomycin) |
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Definition
| Incorporates lactate into Vancomycin so it can't bind, and gets rid of non-resistant forms. Requires many genes (VanA, VanH, VanX, VanY) |
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Term
| Biggest barrier to interspecies gene transfer |
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Definition
| The need for homologous recombination |
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Term
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Definition
| Brings together 2 pieces of DNA for homologous recomb |
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Term
| How many BP must match for RecA to work |
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Definition
| ~100 BP. This is a tough barrier to overcome; low probability of a foreign gene matching 100bp randomly |
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Term
| What process circumvents the barrier of sequence homology and RecA function |
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Definition
| Transposition - two types; cut and paste, and replicative |
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Term
| Three basic types of DNA Transposons (and one mixed category type) |
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Definition
| Insertion sequences, composite transposon, non-composite/simple transposons, (and, conjugative transposons) |
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Term
| Insertion sequence structure |
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Definition
| Transposase gene (1000 BP) with Inverted Terminal Repeats (10-30bp, transposase cutting sites) on each end |
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Term
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Definition
| Two transposons with a gene (≤10K BP) in the middle; outermost ITRs can be cut and moved as a full thing. Each insertion sequence of a composite transposon is called a"Long Terminal Repeat" LTR |
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Term
| Noncomposite/simple transposon |
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Definition
| Long gene (>1000 BP) in between two ITRs. Like a giant insertion sequence |
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Term
| Can transposition ("jumping genes") happen in other things besides bacteria? |
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Definition
| Yes, it can happen in humans - RAGs in Ab/TCR gene assembly |
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Term
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Definition
| Hybrid of transposon and conjugative plasmid; transposon leaves plasmid, conjugates, re-integrates with new cell's plasmid. This optimizes efficiency of horizontal gene transfer |
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Term
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Definition
| Transposons within transposons; selection of any one resistance gene will select for an entire plasmid containing multidrug resistance |
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Term
| Major resistance reservoirs |
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Definition
| Farms (antibiotic feed to fatten livestock, crop dusting) & hospitals (prophylaxis, defensive medicine) |
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Term
| Drug-resistant salmonella |
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Definition
| Subtherapeutic tetracycline to cows --> selected for Salmonella that was resistant to tetracycline AND ampicillin (MDR). People that ate the product and also had ampicillin for strep throat treatment would awaken the dormant salmonella |
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Term
| Triclosan - define, and mechanism of what it would make resistant |
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Definition
| Antibacterial soap. Similar target as Isoniazid for TB therapy, so it may be developing a drug-resistant TB strain |
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Term
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Definition
| Can be used as biomarker for infection to avoid unnecessary AB use |
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