Antimicrobial drugs and drug resistance Flashcards
Penicillin and Cephalosporins are inhibit what part of a bacterium
inhibit cell wall synthesis
what do penicillin and cephalosporin have in common
beta lactam ring
what is a growth factor analong
antibiotic that is chemically similar to a growth factor but due its structural differences it prevents the analog from functioning as a growth factor
penicillin target what in gram positive
transpeptidation
what is an example of a semi-synthetic penicillin that can target gram negative bacteria
ampicillin
sulfanilamide is an example of what
growth factor that inhibits folic acid synthesis, thus nucleic acid synthesis
what is the function of quinolones
inhibits DNA gyrase, prevents supercoiling of DNA
protein synthesis inhibitors target
70S ribosomes
what are the issues of protein synthesis inhibitors
because they target 70S ribosomes, they can target the mitochondria matrix
example of protein synthesis inhibitors
aminoglycosides, tetracycline, macrolides
protein synthesis inhibitor called amino glycosides binding to 30S subunit of the 70S ribosome do what
block translation
what is antibiotic resistance
when an organism develops a mechanism to avoid the activity of an antimicrobial drug that it should be susceptible to
what type of bacteria is high in number on dry skin
betaprotobacteria
what is second highest bacteria on dry skin
corynebacteria
moist skin has high numbers of
corynebacteria and staphylococcus
sebaceous skin has high number of
propionibacteria
actinobacteria produce what as an end product of fermentation
propionic acid
what kind of bacteria can trigger inflammatory acne
propionibacteria acnes
what kind of antimicrobial enzyme in the saliva catalyzes the production of superoxide radicals O2-
lactoperoxidase
streptococcus mutans is what type of bacteria in terms of oxygen
aerotolerant bacteria
what is the end product of fermentation for streptococcus mutans
lactic acid
Helicobacter pylori is a bacterium found in the stomach that causes stomach ulcers, what kind of antibiotic can be administered to it
tetracycline
what is the genus of gram positive latic acid bacteria
enterococcus
what is vancomycin resistant enterococci
strains of entercocci that have developed resistance to vancomycin, a powerful antibiotic often used as a last resort for treating serious Gram-positive infections
what is horizontal gene transfer
the transfer of genetic material to organsims rather than the vertical transmission of DNA from parent to offspring
what do vancomycin and penicillin have in common
they both target transpeptidation in peptidoglycan
examples of bacteria resistance mechanisms
efflux(being pushed out of the cell)
reduced permeability
alteration of target
inactivation of antibiotic
what is an infection
growth of microbes that are not normally present in the host
what is a disease
damage or injury that impairs the host normal function
what is the LD50 value
the dose of a substance that is expected to cause death in 50% of the tested population
what are the steps in pathogenesis at local sites
exposure
adherence
invasive
infection
toxicity
disease
Streptococcus mutans uses slime layer
to stick to teeth
streptococcus pneumoniae uses capsules to
stick to lungs
capsules and slime layers prevent the bacteria from
phagocytes
what are examples of virulence factors
siderophores: iron binding molecules
exoenzymes: proteins that break host tissues
adhesion factors: pili and fimbraie
invasins
toxins: exotoxin and endotoxin
hemolysins
categories of exotoxin
cytoxin
AB toxins
superantigens
what do cytotoxins do
disrupt cytoplasmic membrane
examples of cytotoxins
hemolysins, lecithinase, phospholipase
explain how Leukocidins destroy white blood cells
they insert into the membrane and oligomerize to form a heptamer which acts as a pore that allows contents of the cell to leak and cell dies
explain AB Toxins
b subunit binds to cell receptor which facilitates the entry of the a subunit which exerts its toxin in the cell
example of AB toxins
tetanus, botulism
