Jump to bottom

1 comment

1 Bob Dillon  Mon, Aug 29, 2011 10:33:27am

Engineered Bacteria Secrete Another Species' Toxin to Kill It

Engineered bacteria attack lethal infection with its own weapons.
| August 16, 2011


Engineered bacteria that can detect and kill human pathogens could provide a new way to treat antibiotic-resistant bacteria. Using the tools of synthetic biology, researchers have given bacteria therapeutic properties unseen in any natural strain -- although they won't be injected into people any time soon.

"Our study is the first example of how synthetic biology will be useful for fighting bacterial infections," says biochemical engineer Matthew Chang, an author on the paper, which is published today in Molecular Systems Biology.

Chang and his team at Nanyang Technological University in Singapore have engineered a strain of Escherichia coli bacteria that attacks Pseudomonas aeruginosa, a bacterium that can cause lethal infections.

Pseudomonas aeruginosa competes with its own species by producing toxic proteins called pyocins. Chang's team exploited this molecular system by giving E. coli the genes for pyocin S5, which kills strains of P. aeruginosa that infect people. Because each pyocin targets only certain bacterial strains, the toxin will not kill other bacteria living in the body.

"Pyocins are the Pseudomonas bacterium's own species-specific antibiotics, so using pyocins instead of broad-spectrum synthetic antibiotics might help slow the spread of antibiotic resistance," says Chang.

Pyocin punch

Resistance to pyocins will probably develop more slowly than it does for other antibiotics, says microbiologist Dean Scholl of AvidBiotics in South San Francisco, California, a pharmaceutical company marketing a different type of pyocin. "So far we don't know of any genes for resistance to pyocins that move between bacterial strains on a plasmid, which is how resistance to many small-molecule antibiotics is transferred," he says.

Chang and his team hacked into another aspect of Pseudomonas biology, designing their E. coli to burst open and release pyocins only when they detect the chemical signals that Pseudomonas bacteria send to one another.

In laboratory experiments, only 1% of P. aeruginosa grown in culture with the engineered E. coli survived. Pseudomonas aeruginosa biofilms - bacterial colonies that are more virulent and resistant to antibiotics than lone cells - were also much thinner and sparser when the E. coli were present.

Chang says that the team is refining its E. coli to deliver a greater pyocin punch before moving to animal models.

"This is very elegant biology, but it seems difficult to convert it to a practical system," says David Livermore, a microbiologist at the Health Protection Agency Centre for Infections in London. At present, the treatment is effective only if the engineered E. coli cells outnumber P. aeruginosa by four to one.

"I'd also be very wary of putting live E. coli onto a burn or into the respiratory tract, which is where we often see Pseudomonasinfections, but where you don't want to add bacteria," says Livermore. He thinks that the engineered bacteria might be more useful in treating infections in the gut, where bacteria are already abundant.

The study authors say that their systematic approach to engineering bacteria will make this possible too. "We designed and characterized the three biological elements - toxin production, bacteria sensing and cell lysis - separately," says bioengineer Chueh Loo Poh, another author on the study. "They're just like building blocks, so any combination of them could be interchanged to suit the biology of a different infection."

The team is already engineering another E. coli strain to target Vibrio cholerae, a bacterium that infects the human gut and causes cholera.

This page has been archived.
Comments are closed.

Jump to top

Create a PageThis is the LGF Pages posting bookmarklet. To use it, drag this button to your browser's bookmark bar, and title it 'LGF Pages' (or whatever you like). Then browse to a site you want to post, select some text on the page to use for a quote, click the bookmarklet, and the Pages posting window will appear with the title, text, and any embedded video or audio files already filled in, ready to go.
Or... you can just click this button to open the Pages posting window right away.
Last updated: 2016-01-01 10:29 am PST
LGF User's Guide RSS Feeds Tweet

Help support Little Green Footballs!

Subscribe now for ad-free access!Register and sign in to a free LGF account before subscribing, and your ad-free access will be automatically enabled.

Donate with
Square Cash Shop at amazon
as an LGF Associate!
Recent PagesClick to refresh
Cardboard Cory - The Documentary [VIDEO] Ready to take action? Visit to get started. Senator Cory Gardner (R-CO) is beholden to wealthy right wing special interests, not his constituents. Cory Gardner is afraid of his constituents, unless it's a tightly controlled scripted event. He ...
8 hours, 3 minutes ago
Views: 154 • Comments: 0 • Rating: 1
Tweets: 3 • Share to Facebook
Harris, Parton, Ronstadt on Late Show, March 24, 1999 (Full, Stereo) "Trio II" was recorded in 1994 but not released until 1999, when Emmylou Harris, Dolly Parton, and Linda Ronstadt appeared on Late Show to perform Neil Young's "After the Gold Rush." The Glass Harmonica (or Armonica) was played by ...
1 day, 23 hours ago
Views: 230 • Comments: 1 • Rating: 1
Tweets: 3 • Share to Facebook
Ratched You deserve someone to show you mercy. From the creator of American Horror Story, witness the origin of one of the world's most iconic characters, Nurse Ratched. Sarah Paulson stars in Ratched, coming to Netflix on September 18. SUBSCRIBE: ...
2 days, 22 hours ago
Views: 257 • Comments: 0 • Rating: 0
Tweets: 0 • Share to Facebook
The Jaded Hearts Club - Reach Out I’ll Be There (Official Video) The Official Video for Reach Out I'll Be There by The Jaded Hearts Club. The new album You've Always Been Here is out 2 October, pre-order now: Listen to We'll Meet Again / Reach Out I'll Be There: ...
2 days, 23 hours ago
Views: 339 • Comments: 0 • Rating: 0
Tweets: 1 • Share to Facebook
Raised by Wolves — New Ridley Scott Television Series Mother was programmed to protect everyone after Earth had been destroyed. When the big bad wolf shows up, she is the one we must trust. Subscribe: Be the first to know more:HBO Max: hbom.axLike HBO Max on Facebook: ...
4 days, 22 hours ago
Views: 479 • Comments: 0 • Rating: 0
Tweets: 3 • Share to Facebook
Black Pumas - Confines (Official Live Session With String Quartet) “Confines (Live in Studio)” is available now to stream/download. It is from the deluxe edition of the Black Pumas’ debut album which will be released digitally August 28 and physically October 9. Pre-order in 2xLP, 2xCD and digital formats: ...
6 days, 19 hours ago
Views: 594 • Comments: 0 • Rating: 0
Tweets: 3 • Share to Facebook
Orville Peck - Smalltown Boy (Official Audio) Official audio for Orville Peck’s cover of "Smalltown Boy" by Bronski Beat out now: Pre-save / Pre-add Orville's new EP Show Pony here: Amazon - orvillepeck.lnk.toApple Music - orvillepeck.lnk.toiTunes - orvillepeck.lnk.toSoundcloud -  orvillepeck.lnk.toSpotify - orvillepeck.lnk.toYouTube Music - orvillepeck.lnk.toYouTube - Follow Orville PeckFacebook - facebook.comInstagram - instagram.comTwitter - @orvillepeck LyricsTo ...
1 week ago
Views: 631 • Comments: 0 • Rating: 0
Tweets: 6 • Share to Facebook
Norah Jones - to Live "To Live" is taken from Norah's newest album 'Pick Me Up Off The Floor,' out now and available to stream/download here: Connect with See Norah live: Music video by Norah Jones performing To Live. © 2020 ...
1 week, 4 days ago
Views: 813 • Comments: 0 • Rating: 0
Tweets: 1 • Share to Facebook
Future Islands - for Sure (Official Video) 'For Sure' by Future Islands, out now on all platforms: A Film by Samuel Jerome MasonFinishing by John HarrisonRendered with GarageFarmSpecial Thanks to Anna, Jemima, Mike, Willy, Saad, Eric, Arsen Perish the painI was impoverishedThose ties that windAnd ...
1 week, 4 days ago
Views: 815 • Comments: 0 • Rating: 0
Tweets: 2 • Share to Facebook
Andrew McMahon in the Wilderness - Get on My Wave I wrote and produced “Get On My Wave” with Kyle “King Tuff” Thomas the day we met last summer. I’ve struggled with releasing the song during the pandemic because it felt too happy; detached from the tumult of our ...
1 week, 4 days ago
Views: 794 • Comments: 0 • Rating: 0
Tweets: 2 • Share to Facebook