Exam 3 - Chapter 13 Flashcards
synthetic precursor given to microorganism which completes synthesis of antibiotic with it metabolism
semisynthetic drug
chemical agent made in the lab
synthetic drug
chemical substance produced by microorganisms which have capacity to inhibit the growth of or kill microorganism
antibiotic
property of an antimicrobial drug to be toxic to the microbe with being nontoxic to the host
selective toxicity
5 mechanisms antimicrobial drugs affect the growth of pathogens
- inhibition of cell wall synthesis
- disruption of cell membrane function
- inhibition of protein synthesis
- inhibition of nucleic acid synthesis
- action as antimetabolite
gram positive bacteria are particularly susceptible to
drugs that affect the cell wall
destroy peptidoglycan crosslink and kill bacteria
penicillin, cephalosporin, bacitracin, vancomycin
drugs that inhibit protein synthesis
aminoglycosides, tetracycline, chloramphenicol, macrolides
penicillin inhibits
cell wall
cephalosporin inhibits
cell wall
bacitracin inhibits
cell wall
vancomycin inhibit
cell wall
aminoglycosides inhibit
protein synthesis
tetracycline inhibits
protein synthesis
chloramphenicol inhibits
protein synthesis
macrolides inhibits
protein synthesis
drugs that disrupt cytoplasmic membranes
polyenes and polymyxin
examples of drugs that inhibit nucleic acid synthesis
rifamycin, rifampin, and clofazimine
inhibit transcription of bacterial RNA by binding to RNA polymerase
Rifamycin
more toxic to prokaryotes host and used against TB
Rifampin
binds to DNA of Mycobacterium leprae and prevents normal replication and transcriptionn
clofazimine
agents effective on small number of organisms or a single taxonomic
narrow spectrum drug
type of drug provides minimizes destruction of normal microflora host
narrow spectrum drug
type of drug decreases the chance of resistance
narrow spectrum
effective against a wide number of microorganisms from a wide range taxonomic group
broad spectrum drug
when patient is seriously ill with an infection caused by an unknown organism this type of medicine would be used
broad spectrum
ex of broad spectrum drug
erythromycin
when would you choose a narrow spectrum drug over a broad spectrum
to minimize destruction of microflora of host and decrease chance of resistance
harmful side effects of tetracycline
- produce Gi disorders including liver damager
- enhance activity of blood thinner, warfarin
- reduce effectiveness of oral contraceptives
- shouldn’t take 2nd half of pregnancy
- stain children’s teeth under 5
unique about Clostridium difficile
- major nosocomial infection
- antibiotic-assisted diarrhea (only patients who have been administered antibiotics)
- newborns can act as reservoirs
- doesn’t allow the colon to absorb water causing diarrhea
- big doses of antibacterial drugs will kill good bacteria and let c. diff in
- may persist in hospitals and nursing homes for months or years
resistance
microorganism once susceptible to antibiotic is no longer affected by the drug
factors contribute to antibacterial drug resistance
- globalization
- widespread misuse of antimicrobial drugs
- antibiotics/antibacterial drug in animal feed
- unnecessary prescriptions
- unfinished prescription
spontaneous mutations
lead to resistance in one day
R plasmids and their role in drug resistance
lead to resistance in multiple days
4 mechanisms in which microbes becomes resistant to antimicrobial drugs
- inactivation of the antibiotcs/antibacterial drugs
- efflux pumping of the antibiotic/antibacterial drug
- modification of the antibiotic target
- alteration of pathway
describe the inactivation of antibiotic/antibacterial drug
- enzyme destroys drug
- beta-lactamases
- aminoglycosides
- chloroamphenicol
describe efflux pumping of antibiotic/antibacterial drug
- active transport of drug out of bacterial cell
- tetracycline
- beta-lactams
- fluoroquinolones
describe resistance of medication of antibiotic target
- bacterial ribosomes
- PBP’s (penicillin biding protein)
- erythromycin
- rifamycin
- antimetabolites
superbug
bacteria that is multiple drug resistance
describe ways in which antibacterial drug resistance can be limited
- maintaining high levels of antibiotics in patient long enough to kill all pathogens
- administering 2 antibiotics to get additive effect
- restricting antibiotic use to essential use only
synergism
additive effect when 2 antibiotics are administered at the same time
antagonism
when some drugs are less effective when used in combination than when used alone
example of synergism
Ex. streptomycin + penicillin
Ex. Clavulanic + amoxicllin
Ex of antagonism
Tetracycline (inhibit growth) + penicillin (require growth to be effective)
inhibition of cell wall synthesis
penicillin ampicillin amoxicillin cephalosporin bacitracin carbapenemes vancomycin methicillin
distribution of cell membrane function
polymyxin
inhibit protein synthesis
macrolides (erythromycin, azithromycin) Aminoglycosides (streptomycin, neomycin, kanamycin) chloramphenicol tetracyclines linosamindes (lincomycin, clindamycin)
inhibition of nucleic acid synthesis
rifampin
quinolones (nalidixic acid, ciprofloxacin)
clofazimine
action of antimetabolite
sulfonmides "sulfa drugs" isonized ethambutol trimethoprim nitrofurans
