Preview
Sign-in for full Details 
Sign-in free and Explore the Exciting World of BiomedExperts:
- Over 1.500.000 Profiles
- More than 1.800 Organizations worldwide
- State of the Art Network Visualizations
- Manage your own Profile
- Locate Experts in your Country/Region
- Locate Experts in your 1. and 2. Level Network
- Connect to Experts Worldwide
find experts for
Sign-in to see more
2006:
Nightingale K K; Lyles K; Ayodele M; Jalan P; Nielsen R; Wiedmann M
Novel method to identify source-associated phylogenetic clustering shows that Listeria monocytogenes includes niche-adapted clonal groups with distinct ecological preferences.
Journal of clinical microbiology 2006;
44(
10):.
While phylogenetic and cluster analyses are often used to define clonal groups within bacterial species, the identification of clonal groups that are associated with specific ecological niches or host species remains a challenge. We used Listeria monocytogenes, which causes invasive disease in humans and different animal species and which can be isolated from a number of environments including food, as a model organism to develop and implement a two-step statistical approach to the identification of phylogenetic clades that are significantly associated with different source populations, including humans, animals, and food. If the null hypothesis that the genetic distances for isolates within and between source populations are identical can be rejected (SourceCluster test), then particular clades in the phylogenetic tree with significant overrepresentation of sequences from a given source population are identified (TreeStats test). Analysis of sequence data for 120 L. monocytogenes isolates revealed evidence of clustering between isolates from the same source, based on the phylogenies inferred from actA and inlA (P = 0.02 and P = 0.07, respectively; SourceCluster test). Overall, the TreeStats test identified 10 clades with significant (P < 0.05) or marginally significant (P < 0.10) associations with defined sources, including human-, animal-, and food-associated clusters. Epidemiological and virulence phenotype data supported the fact that the source-associated clonal groups identified here are biologically valid. Overall, our data show that (i) the SourceCluster and TreeStats tests can identify biologically meaningful source-associated phylogenetic clusters and (ii) L. monocytogenes includes clonal groups that have adapted to infect specific host species or colonize nonhost environments.
Post to CiteULike 
Sign in free and see...
Visualized networks:
See your personal network in
sophisticated graphical views
GeoTargeted Searches:
Locate experts around the world
and connect with global collaborators
Research Profiles:
See the visualized research activity
of experts around the globe
Sign-in to see more
