This is a brief overview of antibiotics that target bacterial nucleic acids
This is a video on the classes of antibiotics that target bacterial nucleic acids we’re gonna be talking about antibiotics that target nucleic acids themselves how they’re used or molecules leading up to the synthesis of nucleic acids so before we begin i want to give a brief overview of this pathway that makes tetrahydrofolate acid or tetrahydrofolate tetrahydrofolate
Is integral in making nucleic acids so if we don’t have thf tetrahydrofolate we won’t be able to make nucleic acids the first two antibiotic classes that we’re going to talk about inhibit the pathway that make tetrahydrofolate and first one is sulfonamides now sulfonamides are a class of antibiotics that are bacteriostatic when used alone or bacterial scytl when
Used with this other class of antibiotics that we’ll get into in a bit one example of sulfonamides is sulfamethoxazole abbreviated s mx s mx and tmp are the abbreviations for that this the specific solanum id and the specific trimethoprim now sal fauna are sulfonamides they inhibit the d hps protein which is this protein up here and of course if we cannot make
Tetrahydrofolate we cannot synthesize nucleic acids so this is kind of a way to stop the production of nucleic acids very very high up in the pathway there are a few ways to get resistance to sulfonamides the first way is to mutate the gene that makes this enzyme and there’s a mutation in this gene the enzyme might change enough such that the sulfonamides cannot
Affect it further we can acquire another dhbs protein this can be done through horizontal transfer of genes from one bacteria to the other perhaps there’s a d hps that that alters the binding site so that sulfonamides cannot cannot get there and one last way to to provide resistance to sulfonamides is increased papa production so if you overload this pathway with
This molecule here the pa ba then even though sulfonamides are blocking some of this enzyme you’re still going to get enough through to have normal nucleic acid synthesis as a group as we mentioned a second ago our trimethoprim trimethoprim is abbreviated tmp like we said a second ago it’s bacteria scytl and when it’s used together with sulfonamides the effects
Are synergistic this means that both of the drugs can be used at a lower concentration than what you would normally have to use if you use them individually so these two in the same pathway are synergistic together trimethoprim inhibits the dhfr this is dihydrofolate reductase the enzyme that makes dihydrofolate itself alright these are different antibiotics now
Different classes that are not related to the dihydrofolate pathway first that we want to talk about is quinolones or fluoroquinolones these are some examples of the first-generation quinolone it’s called nalli dicks ik acid and then one of the newer ones is supra flux and which is a second generation in plural quinolone quinolones are bacteria scytl and they
Work by inhibiting dna gyrase and tapio isomerase so these are these are both enzymes that are very crucial to reproduction totu copying dna and if you stop them then you prevent cells from growing there are also a few ways to get resistance to quinolones the first way is to have a mutation in the target proteins if you mutate dna gyrase or top of my summarize then
These antibiotics might not be able to bind to them and then do their inhibitory effect secondly you can decrease the uptake of these antibiotics if you decrease the amount of antibiotic that gets into the cell they might be less effective similarly if you increase the amount of antibiotic that’s pumped out of the cell if you increase the e-flat you get a similar
Effect and there are a few other resistance mechanisms that that kind of relate to resistance mechanisms from other antibiotics this is kind of a an ambiguous thing right here but i just wanted to note that there are other ways to confer resistance to quinolones next group of antibiotics is rhythm ison’s and one example of those is refampin now these can be either
Bacteriostatic or bacterial scytl depending on the concentration depending on the dosage administered they work by binding to rna polymerase which of course makes mrna from the dna this is the process of transcription so these refa myosins are essentially preventing transcription now to get resistance to rhythm essence you want a mutation in rna polymerase which
Is the obviously the enzyme that these rephaim aizen’s bind to one of the last groups we want to talk about is nitro imidazoles and one example of these are metronidazole these are bactericidal and they’re unique in that they work against anaerobic microbes and one last thing to note is that they damage dna that is already made they damage existing dna in the cell
What’s also interesting about nitro imidazoles is that they must be activated by enzymes within the bacteria they are part of a class called pro drugs that’s it’s a group of molecules that that are administered as pro drugs and they become active inside the actual bacterium when they’re activated by microbial enzymes so this has been a brief overview of antibiotics
That target bacterial nucleic acids thanks for listening
Transcribed from video
Antibiotics that target bacterial nucleic acids By MedLecturesMadeEasy
