Antibiotic 'smart bomb' can target specific strains of bacteria
January 30, 2014
Source: North Carolina State University
Summary: Researchers have developed a de facto antibiotic "smart bomb" that can identify specific strains of bacteria and sever their DNA, eliminating the infection. The technique offers a potential approach to treat infections by multi-drug resistant bacteria.
Researchers from North Carolina State University have developed a de facto antibiotic "smart bomb" that can identify specific strains of bacteria and sever their DNA, eliminating the infection.
The technique offers a potential approach to treat infections by multi-drug resistant bacteria. "Conventional antibiotic treatments kill both 'good' and 'bad' bacteria, leading to unintended consequences, such as opportunistic infections," says Dr. Chase Beisel, an assistant professor of chemical and biomolecular engineering at NC State and senior author of a paper describing the work.
"What we've shown in this new work is that it is possible to selectively remove specific strains of bacteria without affecting populations of good bacteria."
The new approach works by taking advantage of a part of an immune system present in many bacteria called the CRISPR-Cas system. The CRISPR-Cas system protects bacteria from invaders such as viruses by creating small strands of RNA called CRISPR RNAs, which match DNA sequences specific to a given invader. When those CRISPR RNAs find a match, they unleash Cas proteins that cut the DNA.
The NC State researchers have demonstrated that designing CRISPR RNAs to target DNA sequences in the bacteria themselves causes bacterial suicide, as a bacterium's CRISPR-Cas system attacks its own DNA.
"In lab testing, we found that this approach removes the targeted bacteria," Beisel says. "We're still trying to understand precisely how severing the DNA leads to elimination of the bacteria. However, we're encouraged by the ease in specifically targeting different bacteria and the potency of elimination."
The researchers tested the approach in controlled cultures with different combinations of bacteria present, and were able to eliminate only the targeted strain.
"For example, we were able to eliminate Salmonella in a culture without affecting good bacteria normally found in the digestive tract," Beisel says. The researchers were also able to demonstrate the precision of the technique by eliminating one strain of a species, but not another strain of the same species which shares 99 percent of the same DNA.
Another benefit of the approach, Beisel says, is that "by targeting specific DNA strands through the CRISPR-Cas system, we're able to bypass the mechanisms underlying the many examples of antibiotic resistance."
The researchers are currently working to develop effective methods for delivering the CRISPR RNAs in clinical settings.
"This sets the stage for next-generation antibiotics using programmable CRISPR-Cas systems," says Dr. Rodolphe Barrangou, an associate professor of food, bioprocessing and nutrition sciences at NC State and co-author of the manuscript.
Steve
Posted by seibertneurolyme (Member # 6416) on :
In theory it sounds great. But with many tickborne patients who do not even know exactly what infections they have I don't think there is much potential for this approach.
Until testing improves and can identify the infections then I can't see much progress in treatment of tickborne diseases.
For instance, how many people could afford to be tested for 30 strains of bartonella to find a match that could be targeted for this type of treatment?
Bea Seibert
Posted by MichaelTampa (Member # 24868) on :
And then still isn't there the issue that the drug has to make it to the bacteria to affect it (hiding in biofilm, not in the blood, ...)
Posted by colonelforbin1992 (Member # 43154) on :
quote:Originally posted by seibertneurolyme: In theory it sounds great. But with many tickborne patients who do not even know exactly what infections they have I don't think there is much potential for this approach.
Until testing improves and can identify the infections then I can't see much progress in treatment of tickborne diseases.
For instance, how many people could afford to be tested for 30 strains of bartonella to find a match that could be targeted for this type of treatment?
Bea Seibert
At the very least though, it sounds like a step in the right direction?
Posted by steve1906 (Member # 16206) on :
Agreed, any step is a good step! At least we have people doing some research.
Steve
Posted by GretaM (Member # 40917) on :
When I read, "sever their DNA", I got ready to get the numbchuks out and do some a$$ whooping on some bacteria!
Steve, put your jock on buddy, the women of LN are tying the bandanas on and gearing up for a martial arts battle!
Pam-where are you, green bandana warrior? Posted by GretaM (Member # 40917) on :
I watched Dr. McD's YouTube about the round forms of borrelia yesterday.
Got thoroughly disgusted at borrelia and the granular version vs. The non-granular version.
But if we could start with ANY bacteria...find a method that works besides antibiotics, then we could use that knowledge for borrelia.
Or the other really awful bacteria, brucella etc.
Why are proteo such devils? Oh right...they steal their hosts DNA... Thieving you-know-whats.
Posted by poppy (Member # 5355) on :
What do they mean by strains, I wonder? This story might be confusing strain with species. Considering there might be many strains of the lyme bacteria, I hope it doesn't really mean strain.
Posted by map1131 (Member # 2022) on :
Here I am, tying on my lyme green bandana. I've got to reread this a few times before I comment.
I've been crushed too many times. It might be a one dose abx tx.
But I'm ready Greta.
Pam
Posted by seibertneurolyme (Member # 6416) on :
Poppy I think they really did mean strains. Because it talked about bacteria with 99 percent DNA match not being affected by the antibiotics.
That is why I said how many people can afford to do PCR tests for 30 strains of bartonella or 300 strains of lyme?
Bea Seibert
Posted by poppy (Member # 5355) on :
Then you are right, Bea. Every patient would need to have a test for their particular strains of each pathogen, and with ticks carrying many....the mind boggles.
Posted by marypart (Member # 27012) on :
Those DNA tests are getting better and cheaper to do. Before long PCR and/or DNA testing is going to be the standard and testing for long lists of possible infections will be routine.
Posted by 'Kete-tracker (Member # 17189) on :
Before anyome gets too excited, ah Bleeve what they refert to is "identifying" (Huh?) and "attacking" the more basic bacteria... Ones that just sit there.. AND are exposed to the blood. B.B. is a "moving target", with a propelling tail.
It may be a step in the right direction, though. I'd love to see a "smart" drug that can target the flagella, making ANY 'kete *immobile* &, hence, unviable... a sitting target!
A 41-kDa-length organic molecule w/ a biological "scissor" oin it's end, anypone?
Posted by Matt S. (Member # 46225) on :
Wouldn't it be possible to use CRISPR-cas on B.B. via the deer? Put the RNA in the deer looking for B.B. and it will eliminate it in the host as well as the ticks. Its exciting to think that we could possibly treat the disease and eliminate it at the source!
Also, I disagree that this would only detect a single strain at a time. I think the article was just trying to demonstrate the pinpoint targeting capabilities of CRISPR.
Radiolab has a recent podcast about CRISPR that dives a bit deeper into how this process works and all the possibilities.
Posted by SacredHeart (Member # 44733) on :
What ever additional weapons can be acquired are great. I hope I can hold on long enough for technology to develop to really put
the nails in the coffin of these diseases. Thanks for the post. Good news always lifts the spirit.
Posted by VV (Member # 38828) on :
quote:Originally posted by seibertneurolyme: In theory it sounds great. But with many tickborne patients who do not even know exactly what infections they have I don't think there is much potential for this approach.
Until testing improves and can identify the infections then I can't see much progress in treatment of tickborne diseases.
For instance, how many people could afford to be tested for 30 strains of bartonella to find a match that could be targeted for this type of treatment?
Bea Seibert
This seems like a pessimistic outlook.
Why not imagine a TBD treatment drug which has a CRISPR marked for every known TBD DNA sequence?
![[Smile]](smile.gif)