2/28/17 Antibiotic Resistance MULVEY TEST #2 Flashcards
What are antibiotics synthesized by?
- Molds
- Bacteria
Who discovered penicillin?
-Alexander Flemming
How many lives do antibiotics save a year?
200,000 +
What are the major antibiotic targets?
- Cell wall
- DNA replication
- RNA synthesis
- Protein synthesis
- Folic acid synthesis
How does antibiotic resistance happen?
-The drug resistant forms don’t die from the antibiotics but the others do allowing the drug resistant forms to grow in the new open space.
What is bacterial resistance facilitated by?
- Chance
- Horizontal gene transfer
- Strong selective pressures from increased use and misuse of antibiotics
There are several antimicrobial resistance mechanisms today, which one is when a drug can’t get in or the drug gets in but gets pumped back out before affecting the target?
-Restrict antibiotic access
There are several antimicrobial resistance mechanisms , which one is when the target is altered structurally or the target is over expressed, and needs much more drug?
-Modify antibiotic targets
What are the four antimicrobial resistant mechanisms?
- Restrict antibiotic access
- Modify antibiotic target
- Modification of the antibiotic
- Modify expression of bacterial factors needed to active the antibiotic
If you have a mutation in 23S rRNA that protects the bacteria against macrolides such as erythromycin what resistant mechanism is that?
-Modify antibiotic target
What does vancomycin bind to, to be effective?
-The terminal D-Ala D-Ala on the protein
For Vancomycin resistance what happens with the D-Ala D-Ala region?
-The second D-Ala gets changed so that Vancomycin can’t bind there anymore
If the transpeptidase is altered so that penicillin can no longer bind to inhibit the transpeptidase, what is the resistant mechanism?
-Modify antibiotic target
When you have B-lactamase that destroys the B-lactam ring what resistant mechanism is that?
-Modification of the antibiotic
When you have modifications that disrupt the hydrogen-bonding network that is used from the antibiotic that is used to bind the 16S rRNA what is the resistant mechanism?
-Modification of the antibiotic
Metronidazole activation is done by what?
-Flavodoxin found in H. pylori and P. gingivalis
What are two drugs that bacteria have become resistant to through the mechanism of resistance by modifying expression of bacterial factors needed to activate that antibiotic?
- Metronidazole
- Isoniazid
What is Isoniazid activated by?
-Bacterial catalase/peroxodase enzyme KatG in MTb
T/F Resistance is acquired by mutation and by Horizontal Gene Transfer
True
T/F Overuse of antibiotics, overpopulation, poor hygiene and travel contribute to the selection and spread of multi-drug resistant strains.
True
What are four multi drug resistant bacterial pathogens?
-Extended-spectrum B-lactamase producing enterobacteriaceae
=Cabapenem-Resistant Enterobacteriacea
-C. diff
-Super N. gonorrhea
What are four reasons that antibiotic tolerance is important?
- Within intracellular niches
- Spores
- Within biofilms
- Persister cell formation
T/F Antibiotic tolerance contributes to chronic and recurrent/relapsing infections (recrudescence)
True
T/F Bacteria that are normally susceptible to antibiotics may be able to tolerate the drugs under some conditions
True
What are dormant bacteria that are insensitive to many stresses and antibiotic treatments called?
-Persister cells
