Featured Research

from universities, journals, and other organizations

Rethinking bacterial persistence: Optofluidics allow for new understanding of resistance to antibiotics

Date:
January 3, 2013
Source:
Ecole Polytechnique Fédérale de Lausanne
Summary:
Scientists have used microfluidics to observe the behavior of individual tuberculosis-like bacteria in the presence of antibiotics. Their observations call into question the prevailing theory of bacterial resistance, and they have proposed a new explanation for why some bacteria become resistant.

Mycobacterial culture. The bacterial genus Mycobacterium includes members that are pathogenic to human beings, and includes Mycobacterium tuberculosis, which caused tuberculosis, and M. leprae, which is the cause of leprosy.
Credit: CDC/ Ronald K. Smithwick

It's often difficult to completely eliminate a bacterial infection with antibiotics; part of the population usually manages to survive. We've known about this phenomenon for quite some time, dating back nearly to the discovery of penicillin. For more than 50 years, scientists have believed that the resistant bacteria were individuals that had stopped growing and dividing.

Up to now, in fact, it hasn't been possible to track the growth of cells before and after their exposure to antibiotics, which makes any analysis of the phenomenon quite imprecise. "Using microfluidics, we can now observe every bacterium individually, instead of having to count a population," says John McKinney, director of EPFL's Microbiology and Microsystems Laboratory (LMIC).

Active survivors

This new tool has revealed quite a few surprises. "We thought that surviving bacteria made up a fixed population that stopped dividing, but instead we found that some of them continued to divide and others died. The persistent population is thus very dynamic, and the cells that constitute it are constantly changing -- even though the total number of cells remains the same. Because they're dividing, the bacteria can mutate and thus develop resistance in the presence of the antibiotic," explains LMIC scientist Neeraj Dhar.

This point is extremely important. "We were able to eliminate a purely genetic explanation of the phenomenon," continues Dhar. In other words, "a population of genetically identical bacteria consists of individuals with widely varying behavior. Some of them can adapt to stressors that they have not previously encountered, thanks to the selection of persistent individuals. This could lead to a revision of the entire theory of adaptation," says McKinney.

Intermittent efficiency

The EPFL scientists were particularly interested in a relative of the tuberculosis bacterium. Their observations enabled them to formally challenge the argument that persistent bacteria are those that have stopped growing and dividing. "We were able to reveal the role of an enzyme whose presence is necessary in order for the antibiotic to work, and show that the bacilli produced this enzyme in a pulsatile and random manner," explains Dhar. "Our measurements showed that bacterial death correlated more closely with the expression of this enzyme than with their growth factor." The research is being published this week in Science magazine.

These conclusions could mark the beginning of a new theory of bacterial resistance, or perhaps even introduce a new view of how such resistance evolves. Further research is being done using other microorganisms, such as tuberculosis and E. coli bacteria. The persistence of some cancer cells to treatment could also be studied in a different manner. "It's a new approach for trying to figure out why some infections are so difficult to eliminate. The techniques we've developed for this study are now also being used to develop new antibiotics, in collaboration with pharmaceutical companies," says McKinney, adding that "it is the microengineering expertise at EPFL that has enabled us to create these innovative tools and open up new avenues for investigation."


Story Source:

The above story is based on materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.


Journal Reference:

  1. Y. Wakamoto, N. Dhar, R. Chait, K. Schneider, F. Signorino-Gelo, S. Leibler, J. D. McKinney. Dynamic Persistence of Antibiotic-Stressed Mycobacteria. Science, 2013; 339 (6115): 91 DOI: 10.1126/science.1229858

Cite This Page:

Ecole Polytechnique Fédérale de Lausanne. "Rethinking bacterial persistence: Optofluidics allow for new understanding of resistance to antibiotics." ScienceDaily. ScienceDaily, 3 January 2013. <www.sciencedaily.com/releases/2013/01/130103143159.htm>.
Ecole Polytechnique Fédérale de Lausanne. (2013, January 3). Rethinking bacterial persistence: Optofluidics allow for new understanding of resistance to antibiotics. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2013/01/130103143159.htm
Ecole Polytechnique Fédérale de Lausanne. "Rethinking bacterial persistence: Optofluidics allow for new understanding of resistance to antibiotics." ScienceDaily. www.sciencedaily.com/releases/2013/01/130103143159.htm (accessed April 19, 2014).

Share This



More Plants & Animals News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) — Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) — Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) — Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) — A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins