A Novel Study Discovers a New Communication System between Streptococci

Study Funded Under the Frame of ERA-NET PathoGenoMics,Published in PLoS
Pathogens

JUELICH, Germany--(Business Wire)--
Group A streptococcus (GAS) is a human pathogenic bacteria. Many people carry
GAS asymptomatically in their upper respiratory tract and other anatomic sites.
However, these bacteria can cause a variety of human diseases ranging from
superficial skin and throat infections to highly invasive life-threatening
diseases such as toxic shock and necrotizing fasciitis, commonly known as the
flesh-eating bacteria. Along with the consequences of autoimmune complications
of rheumatic fever and rheumatic heart diseases, a conservative estimate of
500,000 deaths per year globally due to GAS infections has been calculated,
placing this bacterium as one of the top 10 infectious causes of mortality.

Little is known about what controls the conversion of the bacteria from a
non-harming form to the pathogenic state in GAS infections. Since these bacteria
generally exist as communities and not as solitary microorganisms, bacterial
communication systems are key elements in determining host-bacterial
interactions. Most communication between bacterial cells is done by signaling
molecules secreted and sensed by the bacteria. When the level of the signaling
molecules is high enough, they can activate the expression of genes that
coordinate their behavior. This activation only takes place in the presence of a
sufficient number (a quorum) of bacteria, giving this mechanism the name
quorum-sensing.

A novel research, led by Professor Emanuel Hanski from the Department of
Microbiology and Molecular Genetics at the Medical School of the Hebrew
University of Jerusalem, (Belotserkovsky et al., PLoS Pathogens 5(11): e1000651;
http://dx.plos.org/10.1371/journal.ppat.1000651), identified a new array of
genes in GAS and in a close relative, Group G Streptococcus (GGS), usually
considered a commensal that do not harm the host. These genes are activated by a
quorum-sensing peptide termed SilCR. SilCR is not functional in highly invasive
GAS strains, suggesting that this array of genes may be involved in colonization
and establishment of commensal host-bacterial relationships. The researchers
further show that GAS and GGS strains can sense their respective SilCR
molecules, thus coordinating their pathogenicity, and comprising a novel
communication system between these bacteria. The research was funded by the
Chief Scientist Office of the Israeli Ministry of Health, under the framework of
ERA-NET PathoGenoMics, a European Commission funded imitative aiming at
advancing transnational research in genome-based research programs on
human-pathogenic microorganisms.

"This study opens up exciting possibilities for controlling the pathogenicity of
Streptococcus A, which can cause several invasive, life-threatening illnesses,"
said Dr. Marion Karrasch-Bott, Coordinator of ERA-NET PathoGenoMics. "The
researchers not only identified a new genetic element that controls bacterial
virulence, but also an array of genes regulated by this element. This will help
in our understanding of how bacterial-host interactions can lead to mutual
existence in some cases, or to violent infections in other cases, and will
eventually lead to innovative drugs that could prevent the bacteria from making
the wrong decision."

About ERA-NET PathoGenoMics

ERA-NET PathoGenoMics, an initiative funded by the European Commission, has been
set up to establish sustained co-operation between national funding bodies and
to co-ordinate their genome-based research programs on human-pathogenic
microorganisms. The participating ERA-NET PathoGenoMics partner countries and
funding institutions include: Austria, Federal Ministry for Science and Research
(BMWF) and The Austrian Science Fund (FWF); Finland, Academy of Finland (AKA);
France, Institut Pasteur (IP), Ministère de l'Enseignement supérieur et de la
Recherche (MESR) and The National Agency for Research (ANR); Germany, Federal
Ministry of Education and Research (BMBF) and Project Management Juelich (PTJ);
Hungary, Hungarian Academy of Science (HAS) and Hungarian Scientific Research
Fund (OTKA); Israel, The Chief Scientist Office, Israeli Ministry of Health
(CSO-MOH); Latvia, Latvian Council of Science (LCS); Portugal, The Science and
Technology Foundation (FCT); Slovenia, Ministry of Higher Education, Science and
Technology (MHEST); Spain, Ministry of Science and Innovation. For further
information, please visit www.pathogenomics-era.net

ERA-NET PathoGenoMics
Tsipi Haitovsky, Media Liaison
+972-52-598-9892
tsipih@netvision.co.il

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