Term
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Definition
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Term
| When bacteriostatic drugs are withdrawn can bacteria continue to grow? |
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Definition
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Term
| How do most bacteriostatic drugs inhibit growth? |
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Definition
| inhibit protein synthesis |
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Term
| Why are bactericidal drug actions inhibited by a –static drug? |
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Definition
| most bactericidal drugs require cell growth to be effective |
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Term
| Advantages to –cidal drugs |
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Definition
| Reduces the number of bugs, more rapid, irreversible damage to bugs |
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Term
| Disadvantages of –cidal drugs |
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Definition
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Term
| What do –static drugs prevent that give them an advantage? |
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Definition
| inhibition of bacterial toxins and inflammatory mediators |
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Term
| T/F: Two static drugs can be used in combination to kill a pathogen. |
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Definition
| T – if mechanism is in different part or completely different pathways |
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Term
| T/F: The same antibiotic may be cidal or static against different bacteria. |
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Definition
| T – Ex. <color #ff3399>Penicillin</color>– cidal→ pneumococci, static → enterococci |
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Term
| What is the lowest concentration of drug that inhibits the growth of the organism called? |
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Definition
| Minimal Inhibitory Concentration (MIC) |
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Term
| What are the 2 options for MIC testing? |
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Definition
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Term
| How is Turbidity used to determine the MIC? |
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Definition
| Determined by growing organism in tubes then adding various concentrations of drugs, lowest concentration tube where broth is clear. |
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Term
| How is Viability used to determine the MIC? |
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Definition
| Preinoculate blood agar plate then place antibiotic discs, allow to grow then determine zone of inhibition, diameter is compared to standards to determine sensitivity of the organism to that drug. |
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Term
| What is the Minimal Bactericidal Concentration (MBC)? |
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Definition
| Concentration of drug that actually kills the organism rather than the concentration that merely inhibits growth |
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Term
| How is the MBC determined? |
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Definition
| transfer clear broth tube to blood agar plate, MBC is the plate without growth |
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Term
| What type of drugs have an MBC equal or very similar to the MIC? |
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Definition
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Term
| What is the relationship of MBC to MIC in Bacteriostatic drugs? |
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Definition
| The MBC is significantly higher than MIC |
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Term
| T/F MIC and MBC concentrations can be used to compare effectiveness of an antibiotic. |
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Definition
| FALSE – Effectiveness is based on how much of the drug you can actually administer to the patient |
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Term
| Name the five potential bacterial targets for antibiotics |
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Definition
(1) Cell wall synthesis
(2) Cell membrane
(3) DNA replication + Nucleotide Biosynthesis
(4) Topoisomerases
(5) Protein Synthesis |
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Term
| MOA = crosslinking in bacterial cell walls |
|
Definition
• Penicillin
• Cephalosporins
• Carbapenems
• Monobactams |
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Term
Target of Peptide Antibiotics
Give 2 examples. |
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Definition
Target = <b>Cell membrane</b>
<u>Examples</u>:
Polymyxins & Daptomycin |
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Term
| Bacterial target = DNA-directed RNA polymerase |
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Definition
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Term
| What causes an overgrowth of drug resistant strains of Clostridium difficile? |
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Definition
| complication of treatment with <b>Clindamycin -</b> lincosamide antibiotic with a <color #ff9999>high spectrum of action</color> ⇒ suppression of the normal flora of the bowel |
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Term
| Selection of <i>Clostridium difficile</i> in enteric flora leads to… |
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Definition
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Term
| How do autolysins participate in killing the cell when peptidoglycan synthesis is inhibited? |
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Definition
| autolysins activity continues without a new unit to insert and cell will eventually lyse in hypotonic environment. |
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Term
| What type of enzyme are Penicillin Binding Proteins? |
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Definition
| <b>transpeptidase -</b> catalyzes the final crosslinking step in the synthesis of peptidoglycan |
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Term
| What does <color #ff3399>Penicillin</color>do? |
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Definition
| Irreversibly binds at the active site of the transpeptidase enzyme that cross-links the peptidoglycan strands ∴ inhibiting cross-linking |
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Term
| 3 ways a bacteria can develop <color #ff3399>Penicillin</color> Resistance |
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Definition
(1) Production of penicillinases or β-lactamases
(2) Mutated PBP, so <color #ff3399>Penicillin</color> can’t bind
(3) develop tolerance – inactivation of autolysin |
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Term
| β-lactam antibiotics are structural analogs of… |
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Definition
| the <color #cc00cc>D-Ala-D-Ala</color> end of peptidoglycan pentapeptide |
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Term
| Four complications associated with <color #ff3399>Penicillin G</color> |
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Definition
(1) Hydrolysis by gastric acid
(2) Penicillinase sensitivity
(3) Allergic response
(4) Ineffective against <color #cc66ff>G- enterics</color> |
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Term
| Penicillin with the highest activity against<color #FF00FF>G+ cocci & bacilli</color> |
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Definition
| Narrow spectrum <color #ff3399>penicillins</color> |
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Term
| Name the Narrow Spectrum <color #ff3399>penicillins</color> |
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Definition
| Penicillin G & Penicillin V |
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Term
| Broader Spectrum <color #ff3399>Penicillins</color> are effective against… |
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Definition
| <color #FF00FF>G+</color> AND <color #cc66ff>G-</color> enteric bacilli |
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Term
| Examples of Broader Spectrum <color #ff3399>Penicillins</color> |
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Definition
| Ampicillin, Amoxicillin, Cyclacillin, Carbenicillin, Ticarcillin |
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Term
| Antibiotics considered to be <b>Antistaphylocococcal <color #ff3399>Penicillins</color></b> |
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Definition
| <b>Penicillinase Resistant β-lactams</b> Narrow Spectrum + Penicillinase Resistant Drugs |
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Term
| General characteristics of the Antistaph <color #ff3399>penicillins</color> wrt to Pen G |
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Definition
| Lower activity than Penicillen G BUT <b>are resistant to penisillinase</b> |
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Term
| Antibiotic similar in structure & with a MOA identical to that of penicillin |
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Definition
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Term
| How do cephalosporins differ from penicillins? |
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Definition
| ↑acid stability, penicillinase resistance, antigenically dissimilar (↓risk of cross-reactivity) |
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Term
| What is the progression of 1st to 4th generation cephalosporins? |
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Definition
• broadening <color #cc66ff>G-</color>activity + ↓activity against <color #FF00FF>G+</color>
• ↑β-lactamase resistance
• ↑increased capability to enter CSF (meningitis treatment) |
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Term
| What has rendered many 2nd and 3rd generation cephalosporins inaffective? |
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Definition
| Extended Spectrum β-Lactamases (ESBLs) |
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Term
| T/F - addition of clavulanic acid to 2nd generation Cephs would enhance the antibiotic activity. |
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Definition
| <b>FALSE</b> 2nd & 3rd generations are RESISTANT to both penicillinase & cephalosporinase found in the periplasmic space of <color #cc66ff>G-</color> bacteria (i.e., have altered β-lactamases) |
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Term
| Carbapenems are highly resistant to… |
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Definition
|
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Term
| Bacterial MOR toward carbapenams |
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Definition
(1) ↓membrane peremeability (altered porin channels)
(2) development of <b>carbapenemases</b> |
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Term
| Antibiotic that can be used in penicillin allergic patients who have a <color #cc66ff>G-</color> infection |
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Definition
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Term
| drug of choice for <color #0099ff>MRSA</color> |
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Definition
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Term
| First Organism to develop VRSA |
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Definition
| Enterococcus faecalis (<color # FF00FF>G+</color> enteric) |
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Term
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Definition
| <color #FF00FF>G+ organisms</color> ONLY |
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Term
| Bacterial MOR = desentitization of ribosomes to antibiotic |
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Definition
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Term
| Streptomycin: class of antibiotic & action |
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Definition
| aminoglycoside antibiotic with bacteri<b>cidal</b> activity |
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Term
| Side effects of Amionoglycoside use? |
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Definition
| damage to CN VIII and/or kidneys |
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Term
| Bacteri<b>cidal</b> MOA of Aminoglycosides |
|
Definition
<b>(1) disruption of the cell wall</b>
(2) alter bacterial transcription by binding to ribosomal sumbunit & ↑protein error
<b>(3) FINAL RESULT = ↑membrane permeability (leaky protein ∴ ↑↑ antibiotic uptake into cell |
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|
Term
| Daptomycin (peptide antibiotic): bacterial target |
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Definition
| <b>cell membrane -</b> calcium-dependent membrane insertion |
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Term
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Definition
| Irreversibly binds to bacterial cell membrane, rapidly depolarizes the cell membrane, Efflux of K+, Cell death by multiple failures in biosystems |
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Term
| Daptomycin is effective against… |
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Definition
<color #FF00FF>G+ infections</color>ONLY
includes: MRSA, VRE, & <i>S. pyogenes</i> |
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Term
| Why is resistance to Daptomycin rare? |
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Definition
| bc it has a novel MOA that disrupts <b>multiple aspects</b> of bacterial cell membrane function |
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Term
| Bactericidal activity of Daptomycin is inhibited by… |
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Definition
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Term
| Advantage of treatment with Daptomycin |
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Definition
| is bactericidal without producing a cytokine storm (elicits a "quiet death" from bacterial cells) |
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Term
| Antibiotic with MOA involving Nucleotide Biosynthesis activity |
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Definition
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Term
| Sulfonamide: Mechanism of action |
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Definition
| Blocks dihydropteroate synthetase; PABA -X → folic acid (can be overcome by increasing PABA) |
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Term
|
Definition
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Term
| Sulfonamide Resistance develops… |
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Definition
|
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Term
| Combination of Trimethoprim-Sulfamethoxazole is active against |
|
Definition
| broad spectrum activity against aerobic bacteria and pneumocystis |
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Term
| Quinolones: bacterial target |
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Definition
| DNA gyrase, Topoisomerase IV⇒ <b>inhibit DNA replication & Transcription</b> |
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Term
| Quinolones: Spectrum of activity |
|
Definition
BROAD SPECTRUM
<color #cc66ff>G-</color> aerobic, <color #cc66ff>G-</color> enteric rods or cocci, & <color #FF00FF>G+</color> bacteria |
|
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Term
| MOA = distrupt the cell membrane of <color #cc66ff>G-</color> bacteria |
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Definition
| <b>Polymixon -</b> bactericidal against almost all <color #cc66ff>G-</color> bacteria |
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Term
| Drugs can be used to attenuate protein synthesis in Bacteria while host protein remains uneffected because… |
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Definition
| Bacteria have 70S ribosomes with 30S and 50S subunits, while we have 80S ribosomes with 40S and 60S subunits |
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Term
|
Definition
(1) <b>Polymyxin B Sulfate</b> (<color #cc66ff>G-</color> rods, alters cell membranes)
(2) <b>Bacitracin Zinc</b> (<color #FF00FF>Gram+</color>)
(3) <b>Neomycin Sulfate</b> (broad spectrum) |
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Term
| Tetracycline is effective against |
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Definition
| gram + and gram - organisms |
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|
Term
|
Definition
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|
Term
| One of the LEAST toxic antibiotics |
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Definition
|
|
Term
| Lincosamides: Spectrum of activity |
|
Definition
| Broad spectrum including anaerobic bacteria (1°) & G+ infections in penicillin-allergic individuals |
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Term
| Quinupristin/Dalfopristin (Synercid) |
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Definition
| synergistic combination of two individually STATIC streptogrammin agents that when combined are BATERICIDAL against… |
|
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Term
| What are 5 ways to reduce antimicrobial resistance to antibiotics? |
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Definition
(1) Rapid diagnosis to reduce inappropriate use
(2) Shorten duration of therapy
(3) Cycle use of agents in hospitals
(4) Better surveillance to determine resistance frequency
(5) Better control of antimicrobial use in animals |
|
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Term
| What is Innate resistance? |
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Definition
| a trait of bacterial species that was present before the introduction of antimicrobial agents |
|
|
Term
| What is Acquired (Emergent) resistance? |
|
Definition
| antimicrobial agent USE-DRIVEN selection and accumulation of resistant bacterial strains |
|
|
Term
| What are 2 origins of acquired resistance? |
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Definition
| New Single Mutation, Acquisition of DNA from other bacteria (Horizontal Gene Transfer) |
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Term
| T/F Once resistant strains of bacteria are present in a population, exposure to antimicrobial drugs favors their survival. |
|
Definition
|
|
Term
| What are the 5 principles of Antimicrobial Resistance? |
|
Definition
1. Resistance is likely to emerge
2. Progressive
3. Organisms resistant to one drug will become resistant to other drugs
4. Once Appears, declines slowly or not at all
5. Use of antibiotics by one affects others in healthcare environment |
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|
Term
| Can integrons contain simultaneous resistance to several classes of antibiotics? |
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Definition
|
|
Term
| T/F the use of one antibiotic can activate the expression of a whole gene cassette. |
|
Definition
|
|
Term
| How does antibiotic selective pressure create resistance? |
|
Definition
| Cells that have an integron for resistance of a particular antibiotic will survive. Removal of that antibiotic can cause the integron to be lost because its not necessary. |
|
|
Term
| enzyme used by bacteria for drug inactivation |
|
Definition
| β-lactamases (cephalosporinases, carbipenemases) |
|
|
Term
| How do altered porins in <color #cc66ff>G- bacteria</color> create resistance? |
|
Definition
| decreased access to target |
|
|
Term
| How do altered PBP’s create resistance? |
|
Definition
| <color #ff3399>Penicillin</color> cannot bind to the cell’s altered PBP’s allowing cross-linking to occur. |
|
|
Term
| What other proteins can be involved in bacterial resistance to drugs? |
|
Definition
| Outer membrane Proteins (OMP); Porins; PBP |
|
|
Term
| T/F Virtually all <color #cc66ff>G- organisms</color> express a gene for a β-lactamase. |
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Definition
| T – occurs at least in low levels in the periplasmic space |
|
|
Term
| T/F <color #ff3399>penicillin</color> resistance due to β-lactamase production occurs in <i>S. pneumonia</i> |
|
Definition
| FALSE - <i> S. pneumonia</i> are sensetive to clavulanic acid |
|
|
Term
| Antibiotic taget of β-lactamases |
|
Definition
| penicillins and cephalosporins |
|
|
Term
|
Definition
| Clauvanic Acid and Sulbactam |
|
|
Term
| What are persisters? What protects them? |
|
Definition
| small number of dormant survivor bacterial without antibiotic resistance mechanism; Biofilms |
|
|
Term
| Common MOR seen in <color #cc66ff>G- bacteria</color> |
|
Definition
| change in porin channels in Outer membrane (↓ or altered) |
|
|
Term
| β-lactamases sensetive to clavulanic acid |
|
Definition
<color #cc66ff>G-:</color> TEM penicillinase, ESBLs
<color # FF00FF>G+:</color> <i>S. aureus</i> penicillinase |
|
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Term
| β-lactamases RESISTANT to clavulanic acid |
|
Definition
| <color #cc66ff>G-</color> cephalosporinases |
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