Featured Research

from universities, journals, and other organizations

Meningitis: Neisseria meningitidis disseminates itself by sending out 'scouts'

Date:
February 28, 2011
Source:
INSERM (Institut national de la santé et de la recherche médicale)
Summary:
Although, in the majority of cases, the localized presence of Neisseria meningitidis in the throat has no consequence, it can sometimes lead to meningitis or septicaemia. Scientists have recently discovered how this bacterium disseminates, leaving the throat to pass into the bloodstream.

The structure of a pilus. Green: Pilin assembly monomers. Red: Visualization of phosphoglycerol at the surface of the pilus.
Credit: Copyright Inserm, G. Duménil

Although, in the majority of cases, the localized presence of Neisseria meningitidis in the throat has no consequence, it can sometimes lead to meningitis or septicaemia. The seriousness of these two infections is driving researchers from around the world to improve their understanding of the mode of operation of this bacterium, which, once it leaves its favourite location (the throat) becomes extremely dangerous.

Related Articles


The Avenir team directed by Guillaume Duménil within Inserm Mixed Research Unit 970, "Paris centre de recherche cardiovasculaire" at the Université Paris Descartes, has recently discovered how this bacterium disseminates, leaving the throat to pass into the bloodstream.

The results of this research have been published in the 11 February 2011 issue of the journal Science.

Neisseria meningitidis is a bacterium specific to man. It is frequently present in the non-pathogenic state in the throat of healthy carriers (5% to 30% of the population).

Its persistence in the organism can however prove dangerous in some cases. The location where the bacteria multiply, the throat, represents a port of entry, from where it disseminates into the bloodstream and may penetrate into the brain. In both these cases, the infection becomes very serious since it results in septicaemia or meningitis. Unless dealt with quickly, the mortality rate linked to these two infections is very high.

Guillaume Duménil and his Inserm research team were, therefore, interested to understand more about this bacterium which, when it passes into the bloodstream, becomes very dangerous. "Certain advances made in the past few years provided the starting point for this work, which is published in Science", he explained. We know, for example, that Neisseria meningitidis are equipped with special structures known as pili. These allow the bacteria to adhere to the cells of the throat and to multiply and form aggregates there. We are closely studying the main protein which makes up the pili; namely, pilin", adds Guillaume Duménil.

The researchers then discovered that the protein underwent various modifications over time. One of these, in particular, has proved more interesting than the others: The addition of a phosphoglycerol. This chemical group once grafted onto the pilin, gives the signal for dissemination.

Bacteria isolated from the colony depart as "scouts"

Following these initial results, the researchers discovered the presence of a gene which enabled the transfer of phosphoglycerol onto the pilin: the gene, pptB. This gene only becomes fully functional when the bacteria is in contact with the cells lining the wall of the throat. The frantic activity of the pptB gene causes the addition of phosphoglycerol to the pilin. This then loses one of its essential properties: its capacity to form aggregates. As a consequence, some of the bacteria detach themselves from the colony and, little by little, are disseminated. This strategy is used by the bacteria in order to colonize other areas of the throat and to cross the cells lining it. "This phenomena could almost be compared with the formation of metastases in cancer", says Guillaume Duménil.

This is the first time that scientists have been able to accurately identify the chain of events which controls the bacteria in the bloodstream. It is a first step. "We now know how the Neisseria meningitidis passes from the throat into the blood. We hope to be able to demonstrate that an identical process is involved when the bacteria passes from the blood into the brain, instigating meningitis", concludes Guillaume Duménil.

Furthermore, if the researchers were able to find molecules which can block this dissemination, they would have both a preventative tool (blocking colonization from the throat and passage into the bloodstream) and a therapeutic tool (limiting colonization from the blood vessels and transmission into the brain).

Although the strategy developed by Neisseria meningitidis ensures its multiplication in the throat, and therefore its survival over the course of evolution, it is also responsible for the death of the host organism and hence its own death. Further proof that living in harmony with a host is not easy.


Story Source:

The above story is based on materials provided by INSERM (Institut national de la santé et de la recherche médicale). Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Chamot-Rooke, G. Mikaty, C. Malosse, M. Soyer, A. Dumont, J. Gault, A.-F. Imhaus, P. Martin, M. Trellet, G. Clary, P. Chafey, L. Camoin, M. Nilges, X. Nassif, G. Dumenil. Posttranslational Modification of Pili upon Cell Contact Triggers N. meningitidis Dissemination. Science, 2011; 331 (6018): 778 DOI: 10.1126/science.1200729

Cite This Page:

INSERM (Institut national de la santé et de la recherche médicale). "Meningitis: Neisseria meningitidis disseminates itself by sending out 'scouts'." ScienceDaily. ScienceDaily, 28 February 2011. <www.sciencedaily.com/releases/2011/02/110217125117.htm>.
INSERM (Institut national de la santé et de la recherche médicale). (2011, February 28). Meningitis: Neisseria meningitidis disseminates itself by sending out 'scouts'. ScienceDaily. Retrieved January 26, 2015 from www.sciencedaily.com/releases/2011/02/110217125117.htm
INSERM (Institut national de la santé et de la recherche médicale). "Meningitis: Neisseria meningitidis disseminates itself by sending out 'scouts'." ScienceDaily. www.sciencedaily.com/releases/2011/02/110217125117.htm (accessed January 26, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, January 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Florida Might Legalize Black Bear Hunting

Florida Might Legalize Black Bear Hunting

Newsy (Jan. 24, 2015) — A string of black bear attacks has Florida officials considering lifting the ban on hunting the animals to control their population. Video provided by Newsy
Powered by NewsLook.com
Ebola Killing Large Portion Of Ape Population

Ebola Killing Large Portion Of Ape Population

Newsy (Jan. 23, 2015) — Experts estimate Ebola has wiped out one-third of the world&apos;s gorillas and chimpanzees. Video provided by Newsy
Powered by NewsLook.com
Controversy Shrouds Captive Killer Whale in Miami

Controversy Shrouds Captive Killer Whale in Miami

Reuters - Light News Video Online (Jan. 23, 2015) — Activists hope the National Oceanic and Atmospheric Agency (NOAA) will label killer whales endangered, allowing lawyers to sue a Miami aquarium to release an orca into the wild after 44 years. Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
‘Healthy’ Foods That Surprisingly Pack on Pounds

‘Healthy’ Foods That Surprisingly Pack on Pounds

Buzz60 (Jan. 23, 2015) — Some &apos;healthy&apos; foods are actually fattening. Fitness and nutrition expert John Basedow (@JohnBasedow) shines a light on the sneaky foods like nuts, seeds, granola, trail mix, avocados, guacamole, olive oil, peanut butter, fruit juices and salads that are good for you...but not so much for your waistline. Video provided by Buzz60
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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