Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research traces evolutionary path of multidrug-resistant strep bacteria

31.01.2011
Despite penicillin and the dozens of antibiotics that followed it, streptococcus bacteria have remained a major threat to health throughout the world.

The reason: the superb evolutionary skills of this pathogen to rapidly alter its genetic makeup. In a landmark paper published this week in Science, scientists from Rockefeller University and the Sanger Institute have used full genome sequencing to identify the precise steps in the molecular evolution of Streptococcus pneumoniae. Their research shows the changes the genome of this bacterium has undergone in time and during its massive geographic spread over the globe.

According to the World Health Organization, fatal pneumococcal disease — mostly among children from underdeveloped countries — claims an estimated 4 million casualties per year. Humans are not only the primary targets of pneumococcal disease but also represent the major and possibly the only ecological reservoir on our planet for this bacterial species, which colonizes the nasopharynx of preschool age children.

The researchers, led by the Sanger Institute's Stephen D. Bentley, used high resolution genome sequencing on clinical isolates of S. pneumoniae provided by a number of collaborating laboratories, including the Laboratory of Microbiology and Infectious Diseases at Rockefeller University, headed by Alexander Tomasz. With data available for the date, geographic site and infection site of these isolates, Bentley and colleagues were able to produce a roadmap for the evolution of a major multidrug resistant clones of pneumococci known as the PMEN clone 1, sequence type 81.

The scientists pinpointed the probable date of birth, 1970, and the likely birthplace, Europe, of this extremely successful multidrug resistant clone. The clone then spread to South and North America, South Africa and Asia. The presence of this clone in 12 New York City hospitals was demonstrated by Tomasz's group in 2001. Perhaps more importantly, the findings provide evidence that the mechanism of genetic change in S. pneumoniae is primarily not through acquisition of point mutations but more often — 88 percent of the time — through genetic recombination.

"The phenomenon of genetic transformation, which led Oswald Avery and his Rockefeller colleagues in 1944 to identify DNA as the genetic material, is the very process that Streptococcus pneumoniae uses during evolution in its real in vivo environment," says Tomasz.

Other phenomena first identified in the laboratory also appear in stages of pneumococcal evolution in vivo. For instance, at least some of the recombination changes observed among the clinical isolates seem to use the "competence" system, a DNA uptake mechanism induced by a specific bacterial quorum sensing agent first detected by Tomasz and colleagues in laboratory experiments. Also, the mechanism of penicillin resistance, first identified by Tomasz and colleagues in the 1980s as changes in the affinity of penicillin target proteins known as penicillin binding proteins, or PBPs, is shown to involve the borrowing of genes from other bacteria, a finding previously documented in studies of individual penicillin resistant isolates.

"Perhaps the most fascinating part of the research is the description of how rapidly this clone has responded to massive in vivo interventions in the clinical environment, such as the introduction of penicillin and other antibiotics and — more recently — the introduction of conjugate anti-pneumococcal vaccines," says Tomasz. "These vaccines are directed against the most abundant serotypes of this bacterium, which are carried in the nasopharynx of children and which cause invasive disease."

"This research also demonstrates the importance of close collaborations between groups like the Sanger Laboratory, with expertise in high resolution genomic analysis, and laboratories that can provide carefully characterized collections of bacterial isolates, such as ours. This type of collaboration fits well with the Rockefeller University's tradition of engaging in studies that combine clinical with translational science," says Tomasz. "Such an alliance between molecular biology and epidemiology promises further interesting insights into the mechanism of bacterial evolution in vivo. It may ultimately allow us to understand PMEN-1's secret of success – to learn why this clone was able to spread so widely while others died off."

Joseph Bonner | EurekAlert!
Further information:
http://www.rockefeller.edu

More articles from Life Sciences:

nachricht Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?
26.05.2017 | Paul-Ehrlich-Institut - Bundesinstitut für Impfstoffe und biomedizinische Arzneimittel

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>