Team discovers evolutionary mechanism that allows bacteria to resist antibiotics

January 23, 2015, Saint Louis University
SLU scientist aims to improve antibiotics to treat staph infections
Mee-Ngan F. Yap, Ph.D., assistant professor of biochemistry and molecular biology at Saint Louis University  

In research published in Proceedings of the National Academy of Sciences, assistant professor of biochemistry and molecular biology at Saint Louis University Mee-Ngan F. Yap, Ph.D., discovered new information about how antibiotics like azithromycin stop staph infections, and why staph sometimes becomes resistant to drugs.

Her evidence suggests a universal, by which the eludes this kind of drug, offering scientists a way to improve the effectiveness of antibiotics to which bacteria have become resistant.

Staphylococcus aureus (familiar to many as the common and sometimes difficult to treat ) is a strain of bacteria that frequently has become resistant to antibiotics, a development that has been challenging for doctors and dangerous for patients with severe infections.

Yap and her research team studied staph that had been treated with the antibiotic azithromycin and learned two things: One, it turns out that the antibiotic isn't as effective as was previously thought. And two, the process that the bacteria use to evade the antibiotic appears to be an evolutionary mechanism that the bacteria developed in order to delay genetic replication when beneficial.

The team studied the way antibiotics work within the ribosome, the site where bacteria translates the genetic codes into protein. When the bacteria encounter a potential problem in copying its genetic material, as posed by an antibiotic, it has a mechanism to thwart antibiotic inhibition by means of "ribosome stalling" that is mediated by special upstream peptide elements.

As the bacteria's ribosome copies the strings of genetic code, "ribosome stalling" at upstream elements often promotes the rearrangement of messenger RNA and activates downstream translation of the resistance gene.

Many resistant pathogens exploit this mechanism to up-regulate antibiotic resistance genes, and so survive even in the presence of antibiotics. In effect, the delay allows the bacteria to prepare a defense against the antibiotic further down the line of genetic code.

Yap found that the azithromycin-bound ribosomes do not simply stall at random residues, but only at specific sites. Intriguingly these residues seem to be the preferred stalling site in the "ribosome stalling" peptide elements that stop genetic activity.

"Here we describe, to our knowledge, the first genome-wide snapshot of ribosome distribution along messenger RNAs in Staphylococcus aureus," Yap said. "By globally mapping the position of stalled ribosomes in azithromycin-treated staph, we identified the proteins affected by this antibiotic.

"Our results reveal a striking similarity of stalling motifs that strongly suggests a universal stalling mechanism," Yap said. "We have identified what appears to be an evolutionary mechanism developed by bacteria to counteract the type of that includes azithromycin, called macrolides."

Yap hopes this new understanding of how antibiotic resistance occurs will offer opportunities to improve existing drugs' effectiveness and give doctors more tools to help patients with severe infections.

Explore further: How bacteria evolve defenses to antibiotics

More information: Proceedings of the National Academy of Sciences, www.pnas.org/content/111/43/15379.full

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ch0senbygrace
1 / 5 (14) Jan 23, 2015
Yeah that really proved evolution, cuz the title said so kids, and it's on a purely ''science'' website, so it must be true! Delusional. Talk about crap of the gaps, thisnarticle was one big gaping hole with that misleading title. Might asnwell said super hero comics prove evolution, or that workd record breakers prove we're evolving, look at me I broke my record of lifting 500 pounds, I evolved! So stupid what atheists and chrisitian haters believe. Once again atheists: wherebdo morals come from? And why are their any living fossils, what caused the alleged big bang and how do you explain that theories' many flaws, and what caused the shroud of turnin, and on, and on, and on.
kochevnik
5 / 5 (2) Jan 23, 2015
Finding these delay sites is a great development for targeting. Finally we can look at concrete mechanisms instead of just spraying every permutation of molecules at petri dishes
T2Nav
5 / 5 (5) Jan 24, 2015
I'm afraid CG lost me at "cuz". Good article, BTW. I suspect antibiotic resistance (which too few people & antibiotic-overusers are familiar with) is going to be big, disastrous news a few years down the road. I cheer for every great mind we can throw at it.
simzy39
5 / 5 (6) Jan 24, 2015
CG, can you please stop coming to this website? I honestly hope you aren't in a position to influence any children, including your own. You need to go read 'A Brief History of Time' by Stephen Hawking, along with 'The God Delusion' by Richard Dawkings, and also 'On the Origin of Species' by Charles Darwin.
I'm not saying that your God isn't real but that there really was a lot of logic and evidence that lead to our theories/explanations of the universe. People didn't just get drunk and make them up. In Hawking's book, using logic and observation, he seriously disproves Genesis, and provides really good arguments for how we know there was a Big Bang, and how we know the universe is expanding. It's kinda not just a thoery, there is evidence.
Now, Hawking himself says that he isn't saying God isn't real but that God can only exist before the Big Bang. I mean, can't you just hold onto your irrational belief and just assume that God made the Big Bang? Instead of dismissing science.
simzy39
5 / 5 (8) Jan 24, 2015
Ren, what the heck are you talking about? Are you another crazy evangelist? Why do you religious nuts hang out on a science website?
mooster75
4.3 / 5 (6) Jan 24, 2015
> simzy39

Man does not need to read propaganda represented as science by mass illusionist and to listen some "experts" and "scholars" how must think. These books that you recommend have nothing to do with reality and this man will do yourself a favor if you miss.

Well, could you at least listen to your English teacher and learn how to write properly?
Maggnus
4.9 / 5 (7) Jan 24, 2015
I'm not saying that your God isn't real but that there really was a lot of logic and evidence that lead to our theories/explanations of the universe.
Well, then allow me to say it for you. This god entity that Christians, Moslems and Hebrews try to shove down the throats of everyone else is not real.
People didn't just get drunk and make them up.
That is literally how they made up this god entity. They got drunk (or high, or delusional) and made it up.
jsdarkdestruction
5 / 5 (1) Jan 24, 2015
Sorry about the 4 star up above Magnus. I was aiming for the 5.
simzy39
not rated yet Jan 25, 2015
Magnus, I'm one of the science advocates. The 'People didn't just get drunk and make them up,' is talking about the three books that I recommended, but mainly the theory of evolution, and the Big Bang. I thought it was obvious to know what I talking about if you read all of what I wrote. I even said "I mean, can't you just hold onto your irrational belief and just assume that God made the Big Bang? Instead of dismissing science." Notice how I called it an 'irrational belief'? But truth be told, he can still believe that God made the Big Bang theory. I would rather get the religious nuts to all believe this then to dismiss it (the Big Bang). I was trying to remain polite and not so political, only showing my anger by adding the word 'irrational,' which I knew would go over their heads.
Write some comments targeting CG and Ren.
simzy39
1 / 5 (2) Jan 25, 2015
jsdarkdestruction, you're a moron.

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