Antibiotic Flashcards
Exam 3
bacterial antagonism
antibiotics
antibiotics can be either
semi-synthetic or synthetic
agents that either kill or inhibit growth of different species of bacteria
antibiotics
how do antibiotics kill bacteria?
6 key strategies that usually focuses synthesis of a process
penicillin
cell wall synthesis
antibitoics can come from
natural secondary metabolic products from microbes s
fluoroquinolones
DNA replication
rimfampicin
RNA synthesis
tetracyclines, chloramphenicol
protein synthesis
sulfonamides
folic acid synthesis
daptomycin in gram positive
and
colistin in gram negative
membrane disruption
bactericidal
agents that kill
bacteriostatic
inhibit growth of bacteria
makes a break and rejoins the strands
gyrase
covalently link to gyrase and cause lethal double stranded DNA break
fluoroquinolones
pencillin binding protein
transpeptidase
what is similar between the penicillin and the D-Ala D-Ala
beta lactam ring
penicillin prevents the binding of
transpeptidases to D-ALA D-ALA
Rifampcin binds to _____ and blocks trancription-elongation
RNAP
Bacteria must synthesize folic acid from
PABA
a precursor of DNA and is impermeable to bacterial cell
Folic acid
inactivating the antibiotic
beta-lactam resistance
Beta lactamase
cleaves the beta lactam ring inactivating penicillin
Beta lactamase is secreted from the _____ and the gene is often encoded on a ______ and is inducible
Beta lactamase is secreted from the cytoplasm and the gene is often encoded on a plasmid DNA and is inducible
vancomycin resistance
modifying or replacing the target
vancomycin binds to the ________ in the PG and prevents ________ access to the substrate
vancomycin binds to the D-ALA D-ALA in the PG and prevents transpeptidase access to the substrate
Vancomycin results when an enzyme changes s_____ to _______ leading to no binding of vancomycin and ________ is able to access the substrate
Vancomycin results when an enzyme changes D-ALA to D-ALA Lactate leading to no binding of vancomycin and transpeptidase is able to access the substrate
remove the antibiotic from the cell: efflux pumps
multi drug resistance
prevent antibiotic uptake by decreasing ______ gene expression in Gram negative, or by _______ the thickness of the peptidoglycan cell wall, or by forming a _____ or producing a _______
prevent antibiotic uptake by decreasing OMP gene expression in Gram negative, or by increasing the thickness of the peptidoglycan cell wall, or by forming a capsule or producing a Biofilm
cells neither grow nor die during antibiotic exposure
develop persister populations
persister cells are metabotically
inactive
by being inactive persister cells are able to survive the
antibiotic Tx
organism is innately resistant to the antibiotic
intrinsic resistance
organism develops the ability to resist the antibiotic through acquiring mutations or new gene via horizontal gene transfer
acquired resistance
why is gram negative resistance to vancomycin?
drug is too big to pass through the outer membrane porins
why gram postive resistance to colistin?
lack of outer membrane LPS
