Featured Research

from universities, journals, and other organizations

Computational methods reveal how hospital-acquired bacteria spread

Date:
January 16, 2013
Source:
Suomen Akatemia (Academy of Finland)
Summary:
New methods are being used to develop models of the evolution of bacteria and viruses. “Essential for the evolution of the bacteria that cause hospital-acquired infections is the horizontal gene transfer. It means that several different cell processes transfer genes between the lineages of the same and different species so that the bacterium becomes resistant to antibiotics and the virulence factor rapidly spreads in the population,” explains a researcher.

The new methods are used to develop models of the evolution of bacteria and viruses. "Essential for the evolution of the bacteria that cause hospital-acquired infections is the horizontal gene transfer. It means that several different cell processes transfer genes between the lineages of the same and different species so that the bacterium becomes resistant to antibiotics and the virulence factor rapidly spreads in the population," explains group leader, Professor Jukka Corander. Corander's group is part of the Centre of Excellence in Computational Inference Research.

This so-called recombination of bacteria makes it much more complicated to carry out evolution analyses. To facilitate such analyses, Corander's group in cooperation with researchers from Harvard University and the Wellcome Trust Sanger Institute has developed a number of methods based on smart randomised algorithms. These methods facilitate efficient and reliable analyses of extensive genomic data. With the current, most commonly used computational methods this work would take several months or even several years.

Two of the group's methods have recently been applied by an international study. This study demonstrated that more than half of the genetic variation of the MRSA bacteria (i.e. methicillin-resistant strains of Staphylococcus aureus) is caused by horizontal genomic transfer. This shows that the evolutionary analyses of the strains of bacteria are necessary when investigating the spread of bacteria in a host population. This horizontal variation significantly distorts the results received from normal evolutionary analyses.

"On the basis of the results from these analyses, i.e. the evolutionary variation, we're able to estimate when a certain strain of the MRSA bacterium has entered a country and started to spread to hospitals. This is the first time we have been able to prove that the interplay between the horizontal genomic variation and the mutational genomic variation may vary significantly across geographical locations and even between individual hospitals," Corander says. According to Corander, these insights open up new opportunities for in-depth studies on the spread and variation of MRSA and related causalities.

In another recently published study, Corander's group investigated the origin and evolution of the Enterococcus faecium bacterium that has adapted to survive in hospital environments. By using its analysis methods, the group found out that the forms of the bacteria originate from several independent sources, which is contrary to previous knowledge. In the nuclear genome of hospital strains of E. faecium, fewer signs of horizontal transfer were found than expected. This discovery led to a hypothesis that strains of bacteria that have adapted to survive in hospital environments may become either genetically or ecologically more isolated after horizontal transfer.

MRSA is a globally spread bacterium that is especially troublesome in hospitals. It is resistant to most antibiotics and annually causes the death of tens of thousands of people in the US, for instance. According to cautious estimates, the annual costs incurred by MRSA infections amount to several billion US dollars. In recent years, the E. faecium bacterium has become one of the major causes of hospital-acquired infections and its antibiotic-resistant strains have caused severe hospital epidemics worldwide.


Story Source:

The above story is based on materials provided by Suomen Akatemia (Academy of Finland). Note: Materials may be edited for content and length.


Journal References:

  1. Santiago Castillo-Ramirez, Jukka Corander, Pekka Marttinen, Mona Aldeljawi, William P Hanage, Henrik Westh, Kit Boye, Zeynep Gulay, Stephen D Bentley, Julian Parkhill, Matthew T Holden, Edward J Feil. Phylogeographic variation in recombination rates within a global clone of Methicillin-Resistant Staphylococcus aureus (MRSA). Genome Biology, 2012; 13 (12): R126 DOI: 10.1186/gb-2012-13-12-r126
  2. R. J. L. Willems, J. Top, W. van Schaik, H. Leavis, M. Bonten, J. Siren, W. P. Hanage, J. Corander. Restricted Gene Flow among Hospital Subpopulations of Enterococcus faecium. mBio, 2012; 3 (4): e00151-12 DOI: 10.1128/mBio.00151-12

Cite This Page:

Suomen Akatemia (Academy of Finland). "Computational methods reveal how hospital-acquired bacteria spread." ScienceDaily. ScienceDaily, 16 January 2013. <www.sciencedaily.com/releases/2013/01/130116090640.htm>.
Suomen Akatemia (Academy of Finland). (2013, January 16). Computational methods reveal how hospital-acquired bacteria spread. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2013/01/130116090640.htm
Suomen Akatemia (Academy of Finland). "Computational methods reveal how hospital-acquired bacteria spread." ScienceDaily. www.sciencedaily.com/releases/2013/01/130116090640.htm (accessed August 22, 2014).

Share This




More Plants & Animals News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Endangered Red Wolves Face Uncertain Future

Endangered Red Wolves Face Uncertain Future

AP (Aug. 22, 2014) A federal judge temporarily banned coyote hunting to save endangered red wolves, but local hunters say that the wolf preservation program does more harm than good. Meanwhile federal officials are reviewing its wolf program in North Carolina. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Farm Resurgence Grows With Younger Crowd

Farm Resurgence Grows With Younger Crowd

AP (Aug. 22, 2014) New England farms are seeing a surge in younger farm hands as the 'buy local' food movement grows across the country. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) According to a new study, spiders that live in cities are bigger, fatter and multiply faster. 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