Week 13- Antimicrobial drugs Flashcards
Differentiate between an antimicrobial drug/agent and a true “antibiotic”
Drug/agent– will treat an infectious disease
true antibiotic— is produced naturally by an organism
Which Genus of bacteria produces many of the antibiotics that humans use?
Streptomyces
What are semisynthetic antimicrobial drugs?
Started with an antibiotic , but then you chemically modify the antibiotic in a lab
What are synthetic antimicrobial drugs?
completely produced in lab
Describe selective toxicity of an antimicrobial agent
selectively will try to target/ kill a microorganism
will also not destroy human cells
Briefly DESCRIBE the six main mechanisms of antimicrobial. This is asking –
what are the ways that an antimicrobial drug will try to kill a microorganism?
1-Inhibits formation of cell wall
2-Inhibiting protein synthesis
3-destruction of cell membrane
4-inhibit metabolic pathway
5-inhibit synthesis of dna/rna
6-prevent a mo from attaching/entering cell
Why do antibacterial drugs make up the largest number of antimicrobial drugs?
easier to target prokaryotic cells
because they are not like human cells
Why are there fewer drugs to treat eukaryotic infections (ie protozoa and fungal)?
are similar to human cells
so can only make some that aren’t toxic to humans
Why do antivirals make up the smallest percentage of antimicrobial drugs?
because virus’s enter a blood cell
so you need to target before it enters cells
mainly effective 48 hours before symptoms
Define spectrum of action
Number of different pathogens a drug acts against
narrow spectrum antimicrobials
Kills fewer types of MO
broad-spectrum antimicrobials
Kill more groups/types then narrow
safer option to give because it kills more
Explain the difference between a “susceptible” microbe and a resistant microbe to a specific antimicrobial drug
susceptible- it is killed by the drug
resistant-drug does not kill MO
Describe the “Antimicrobial Susceptibility
Test.”
Place a disk on the streaked plate
disk will either make a ring or won’t-if it makes a ring, you measure it
the rings will be labeled as susceptible, intermediate, or resistant based on comparison size of zones
What is the clinical significance of resistant microorganisms?
If it has a lot of resistance to many drugs, it can cause problems because you will need to keep making more and more drugs until you can eventually kill it
takes a long time
Describe the 3 general side effects (safety issues) of antimicrobial agents— include examples
1-allergies-rash or anaphaptic shock
2-disruption of normal flora- gi symptoms, nausea, upset stomach, diarrhea
3-toxicity to organs-liver, brain & kidneys
Describe 2 general ways resistance in bacteria is acquired by the microorganism (genetically)
Plasmid- Resistance plasmid- resistant to antimicrobial drug
Chromosomes- mutatuions that will help MOnot be killed by drugs
Briefly describe first 5 types of mechanisms microorganisms are able to use to be resistant to antimicrobials (p. 300 text book)—Mechanisms of Resistance
(what are the ways the microorganisms are NOT allowing the drug to work)
1-MO will create an enzyme that can breakdown drug
2-Prevents/slows down entry of drug
3-Alter the target
4-Alter metabolic chemistry
5-Will pump the drug out
Describe the ways that resistance to antimicrobial drugs can be prevented?
1-only take a specific drug when it is necessary(have MO in you)
2-Drug needs to be taken for the entire time
3- two antimicrobial drugs at one time
4-modifying or making new drugs
What are some common “resistant” microorganisms?
MRSA
VRSA
VRE
