Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic evidence for single bacteria cause of sepsis identified for the first time

21.03.2014

University of Leicester academic involved in study into single bacteria causes of systematic disease

An international team of academics, including Professor Marco Oggioni from the University of Leicester's Department of Genetics, has studied how localised infections can turn into the dangerous systematic disease sepsis – and has identified for the first time through genetic evidence that a single bacteria could be the cause.


Rather than from a mixture of cooperating bacteria, sepsis seems to originate from a single bacterial cell.

Credit: Image credit: Marco R. Oggioni

The study, which has been published in the academic journal PLOS Pathogens, examined the events that lead to sepsis by Streptococcus pneumoniae (pneumococcus), a major human pathogen, in mice. They found that in most cases the bacteria causing sepsis was started by a single pneumococcal cell.

The study was an interdisciplinary collaboration between the Departments of Genetics, Infection Immunity and Inflammation and Mathematics at the University of Leicester, Professor Richard Moxon at the University of Oxford and scientists from overseas including the University of Siena.

... more about:
»Genetic »bacteria »immune »injected »macrophages »systemic

Professor Oggioni said: "Our data in experimental infection models indicate that we do not need only strategies which target many bacteria when it is too late, but that early intervention schemes which prevent the one-single cell that starts the disease process might provide substantial benefit to the patient.

"In this work we have for the first time provided genetic evidence for a single cell origin of bacterial invasive infection. The scenario was hypothesised over 50 years ago, but so far only phenotypic and statistical evidence could be obtained for this event."

Under normal circumstances, when different bacteria are used in models of experimental infection of hosts who have not previously encountered the same pathogen, the vast majority is destroyed rapidly by the host's innate immune system.

In the researcher's model, a dose of one million bacteria is needed to induce systemic disease in about half of the hosts in the study.

This is in stark contrast to a much lower number of bacteria thought to make up the starting "seed" that leads to the development of systemic infection - and the assumption is that there must be one or more "bottlenecks" in the development of the disease.

To investigate these bottlenecks, the researchers injected mice with a mix of three different variants of S. pneumoniae. About half of the mice developed sepsis and in almost all cases the bacteria causing sepsis were derived from only one of the three variants used in the initial challenge.

Using statistical analysis as well as direct DNA sequencing, the researchers could show that in most cases the bacterial population causing sepsis was started by a single pneumococcal cell.

When the researchers looked closer at how the immune system resists most injected bacteria, they found that macrophages, a type of immune cell that can gobble up bacteria, and specifically macrophages in the spleen, are the main contributors to an efficient immune response to this pathogen.

Their findings suggest that if bacteria survive this initial counter-attack, a single 'founder' bacterium multiplies and re-enters the bloodstream, where its descendants come under strong selective pressure that dynamically shapes the subsequent bacterial population – resulting in the sepsis.

The data also suggests that the single bacterium leading to sepsis has no obvious characteristics that give it an advantage over the 999,999 others, but that random events determine which of the injected bacteria survives and multiplies to cause disease.

It is believed that the findings, suggesting that the development of sepsis starting from a single founding cell which survives the immune system's initial counter-attack in mice, could also potentially apply to human systemic infections.

This information could prove vital to understanding sepsis, as the causes of the disease are still largely unknown to the scientific community.

Dr Oggioni added: "Knowing that there is a moment when a single bacterial cell escapes "normal" immune surveillance at the beginning of each invasive infection is an important paradigm and essential information which, in our opinion, should lead to changes in therapeutic protocols in order to maximise success of treatment outcome."

###

The study, 'The Role of Host and Microbial Factors in the Pathogenesis of Pneumococcal Bacteraemia Arising from a Single Bacterial Cell Bottleneck', has been published in the academic journal PLOS Pathogens on Thursday 20 March.

Marco Oggioni | EurekAlert!

Further reports about: Genetic bacteria immune injected macrophages systemic

More articles from Life Sciences:

nachricht Quasi-sexual gene transfer drives genetic diversity of hot spring bacteria
29.05.2015 | Carnegie Institution

nachricht Scientists use unmanned aerial vehicle to study gray whales from above
29.05.2015 | NOAA National Marine Fisheries Service

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Lasers are the key to mastering challenges in lightweight construction

Many joining and cutting processes are possible only with lasers. New technologies make it possible to manufacture metal components with hollow structures that are significantly lighter and yet just as stable as solid components. In addition, lasers can be used to combine various lightweight construction materials and steels with each other. The Fraunhofer Institute for Laser Technology ILT in Aachen is presenting a range of such solutions at the LASER World of Photonics trade fair from June 22 to 25, 2015 in Munich, Germany, (Hall A3, Stand 121).

Lightweight construction materials are popular: aluminum is used in the bodywork of cars, for example, and aircraft fuselages already consist in large part of...

Im Focus: Solid-state photonics goes extreme ultraviolet

Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.

In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to...

Im Focus: Advance in regenerative medicine

The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.

Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Quasi-sexual gene transfer drives genetic diversity of hot spring bacteria

29.05.2015 | Life Sciences

First Eastern Pacific tropical depression runs ahead of dawn

29.05.2015 | Earth Sciences

Donuts, math, and superdense teleportation of quantum information

29.05.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>