Drug resistance Flashcards
Equation to figure out the probability of antibiotics developing resistance?
Antibiotic 1: 1/10^6
Antibitotic 2: 1/10^6
Antibiotic 1 + Antibiotic 2 = 1/10^12
therefore; combination of 2 antibiotics decreases the chance of antibiotic resistance
Why are Sulfanides used in combination with trimethoprin?
because it blocks 2 different distincs steps in folic acid metabolism - prevents the emergence of exsisting resistant strains
What is combination therapy used for?
temporary treatment until diagnosis is made
another antibiotic synergism: aminoglycosides synergize with beta lactam
caution: antibiotic antagonism with penicillin and bacteriostatic drugs.
How does drug resistance happen?
a drug resistance mutant or drug sensitive is exposed to a drug at LOW CONCENTRATION FOR A SHORT DURATION…
this provides a selective advantage for the drug resistant strains
Which is better.. A)Low concentration/short duration B) high concentration/short duration C)high concentration/long duration D) turtles
C
-a high concentration and a long duration- slows down the drug resistant strains and kills it!!
Who is responsible for drug resistance?
- Misuse of antibiotics
- Farmers- using antibiotics and hormones in their cows
- HCW
- PTS: giving them the drugs when there not really needed
- Antibiotics are sold in 3rd world countries
- Hospitals: where the most popular and deadly drug resistant bacteria’s are.
Briefly list some mechanisms of antibiotic resistance:
Expelling drugs
Degradation (cutting)
Modifying (editing)
Altered target site (still get the activity they need but escape the affects of the antibiotic)
What does altering the target site entail? Where do we see this?
Bacterial cells alter or eliminate the target site for the antibiotics (penicillin binding protein transpeptidase)
Resistant cells may later target drug or eliminate it so that the drug can not bind/attach, or binds less effectively
Seen in antimetabolites and drugs that thward protien translation.
Enzymes that alter the antibiotics to inactivate its function is considered…
inactiviation of antibiotics
Function of calvulinic acid:
binds strongly to beta lactamases - inhibits their activity
synergistic effect with penicillin and cephlasporins.
A common pump that expels antibacterial (tetracylines) drugs from bacterial cells
- powered by ATP
- able to pump more then one type of antimicrobial from cell
What am i?
a) reflux pump
b) pumping pump
c) expelling pump
d) efflux pump
D
Multiple Resistance means that:
Common in:
A pathogen can acquire resistance to more then one drug at a time (different drugs with different chemicals/targets)
Common when R-Plasmids are exchanged
-Happens in hospitals and nursing homes because there is a constant use of multiple drugs at the same time
Cross resistance means:
pathogen can acquire resistance to several antibiotics with similar chemical structure
Resistance to one antimicrobial agent confers resistance to another that is similar
what is NDM-1
A pathogen that originated in india, that was brought to the UK and it is resistant to all antibiotics.
What is beta lactamase?
It’s an enzyme released by bacteria that have grown resistance to penicillins. It secretes the enzyme and the enzyme disables the beta lactam ring of penicillin -
*works against the beta lactam rings in penicillin therefore disabling the antibiotics functions
