Controlling Microbial Growth in the Body: Antimicrobial Drugs Flashcards
Suffix common for the aminoglycosides class?
-mycin
Define ESBL
Extended-spectrum beta-lactamases
Define how inactivation of the drug works
microbe produces enzymes that break down drug i.e. beta-lactamase
What are the key side effects of quinolones and fluoroquinolones?
photosensitivity, hallucinations, and suppresses cartilage development in children
Give examples of beta-lactam drugs and beta-lactamase inhibitors.
beta-lactam drugs- penicillins, monobactams, cephalosporins, and carbapenems
inhibitors- sulbactam and clauvulanate
Define MRSA
Methicillin-resistant staph aureus, must use vancomycin to treat
inhibition of protein synthesis drugs
aminoglycosides and macrolides: end in -cin
tetracyclines: end in -line
streptogramins: synercid
other: chloramphenicol
Which 2 types of microorganisms produce most antibiotics?
bacteria (streptomyces and cephalosporin) and fungi (penicillium and cephlosporins)
How is E test different from Kirby-Bauer?
E test, a strip with varying levels of drug concentrations is placed on a lawn. Where the ellipse connects with the test strip concentration is the MIC.
Which class of antimicrobial is doxycycline?
tertacyclines
Why are sulfonamides not antibiotics?
they are synthetic
Describe how increase in elimination of the drug works
mutations cause increase in efflux pumps which pump drug out i.e. quinolone resistance
Describe 2 ways that you could obtain an MIC. What does MIC stand for?
E test and broth dilution
minimum inhibitory concentration
What was the first antibiotic discovered? By whom? How?
Penicillin, Fleming, staph did not grow around penicillin in plate
What are the key side effects of tetracyclines?
discolors teeth of children and fetus, affects long bone development, not indicated for pregnancy
Describe how decrease in uptake of the drug works
Porins on gram-negative bacteria close
injury to the plasma membrane drugs
polypeptide: bacitracin and polymixin B
What type of enzyme destroys specifically the beta-lactam ring of cephalosporins?
cephalosporinase
Define broad spectrum antibiotics
work against a large variety of bacteria
Define how alteration of the target works
the cellular target of the drug is changed in some way. i.e. Penicillin binding proteins changing
Define CRE
carbapenem resistant enterobacteriaceae
inhibition of folic acid synthesis drugs
sulfonamides: begin with sulfa
trimethoprim
What are three representative macrolides?
erythromycin
clarithromycin
azithromycin
Define bactericidal
kills bacteria
Suffix common for the macrolides class?
-mycin
Why are clavulanate and sulbactam used in combination with some drugs? what do they inhibit?
They are beta-lactamase inhibitors
inhibition of nucleic acid synthesis drugs
rifamycin: rifampin
quinolones: end in acid or floxacin
Define MIC and MBC.
MIC- minimum inhibitory concentration
MBC- minimum bacteriocidal concentration
Define VRE
vancomyocin resesitant enterococci
Define MDR-TB
multidrug resistant TB
What are the key side effects of rifampin?
reddish brown secretions
Suffix common for the carbapenems class?
-penem
Describe how the disk-diffusion method of antimicrobial susceptibility testing (Kirby-Bauer) is performed. What does the zone of inhibition indicate?
Smal disks of multiple drugs of a known amount are placed on the plate to test for susceptibility. Zone indicates how effective the drug is.
Which class of antimicrobial is gentamicin?
aminoglycosides
What are some advantages of the broth dilution method?
Both MIC and MBC can be directly observed in one set of dilutions. Can be miniaturized to test many drugs.
Describe the modes of action of anti-viral drugs and be familiar with the examples given.
attachement antogonists: -arildones (pleconaril) and -neuraminidase inhibitors (tamiflu)
inhibition of nucleic acid synthesis:
acyclovir for herpes
ribavirin for Hep C
base analogs in AZT
reverse transcriptase inhibitor
Which four main classes of antimicrobics contain a Beta-lactam ring(“garage”)? Which type of enzyme, in general, destroys this ring?
penicillins, monobactams, cephalosporins, and carbapenems.
beta-lactamase
Define bacteriostatic
inhibits the growth of bacteria
Suffix common for the penicillin class?
-cillin
Which class of antimicrobial is vancomycin?
glycopeptide, inhibition of cell wall synthesis
Suffix common for the quinolones and fluroquinolones class?
acid or -floxacin
Define synergism and give an example.
two drugs that work together at a greater level. bactrim (sulfonamide and trimethoprim)
Describe the modes of action of anti-fungal drugs and know examples given.
bind to ergosterol in cell membrane: polyenes, nyastatin and amphotericin B
Inhibit synthesis of ergosterol: -azoles (clotrimazole and miconazaole) and allyamines (terbafine)
interfere with mitosis (griseofulum)
interfere with DNA synthesis (5-flucytosine)
Why is it more difficult to develop antimicrobial agents that work against fungi, protozoa, and helminths (eukaryotic microbes)? and viruses? (obligate intracellular parasites).
More difficult because they are either similar to our own cells or rely on our cells
inhibition of cell wall synthesis drugs
penicillins: end in -cilin
cephalosporins: start with ce-
monobactams: end in -nam
carbapenems: end in -em
polypeptides: bacitracin
glycopeptide: vancomycin
What are the key side effects of chloramphenicol?
suppresses RBC production, aplastic anemia
Define VISA
vancomycin intermediate staph aureus
