lecture 34 Flashcards
whats the idea of the magic bullet
a chemical ‘magic bullet’ to kill microbial cells but
not the host’s cells
define antibiotic
a substance that is produced by a microorganism that is antagonistic to growth of other microorganisms
define selective toxicity
being toxic to one specific type of cells and not to others.
how do selectively toxic antibodies discriminate between cells
they exploit structural and or metabolic differences between cell types.
what was the first majorly used antibiotic and how does it work
Penicilin functions to interfere with the normal production of the bacterial cell wall, which it does by inhibiting the formation of the amino acid cross bridges between the strands of peptidoglycan. This occurs as the transpeptidase mistakes the penicilin for the amino acids which should be in the amino acid cross bridge, thus making the transpeptides weak and the cell wall be leaky and bacteria dies.
what other bacterial physiologies can antibiotic target
cell wall, proteins synthesis, bacterial metabolism, plasma membrane, pathogen attachment to host cells, DNA or RNA synthesis.
why have bacteria developed antibiotic resistance
These mutations occur frequently in bacteria due to their large turnover. Penicillin resistance developed via a mutation in a bacteria. This bacteria then spread its mutated gene vertically to offspring.
what other method of gene transfer aids antibiotic resistance
the horizontal gene transfer between bacteria species, they can share their plasmid DNA for resistance.
what gives bacteria resistance against penicillin and how it work
The mutation for penicillin resistance resulted from an ezyme called beta lactamase. This enzyme produced by the bacteria is used to destroy penicillin. Beta lactamase eliminates penicillin by destroying the beta lactam ring on penicillin. Cutting it and making it useless.
when may bacteria be resistance to all antibiotics
2050
why is increased antibiotic exposure a bad thing
Increased exposure of antibiotics to the body is bad as we will give bacteria further beneficial mutations to fight the antibiotic.
what are the 4 ways we can prevent bacteria from becoming completely resistant to antibiotics
Decrease the use of antibiotics
Improve doctor’s diagnostics and refrain from handing out antibiotics as much as possible
Identify new targets for the antibiotics as some pathways are easier to disrupt and some pathways are harder for the bacteria to replace
also combination therapies, and traditional antibiotics can be combined with molecules that block resistance mechanisms.
why don’t we want the antibiotic to target things like the plasma membrane
because it is too similar to our plasma membranes, this may result in the antibiotic being toxic to human cells as well
