IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kalia, A.
Right arrow Articles by Bessen, D. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kalia, A.
Right arrow Articles by Bessen, D. E.

 Previous Article  |  Next Article 

Infection and Immunity, April 2002, p. 1971-1983, Vol. 70, No. 4
0019-9567/02/$04.00+0     DOI: 10.1128/IAI.70.4.1971-1983.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Influence of Recombination and Niche Separation on the Population Genetic Structure of the Pathogen Streptococcus pyogenes

Awdhesh Kalia,1 Brian G. Spratt,2 Mark C. Enright,3 and Debra E. Bessen1*

Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520,1 Department of Infectious Disease Epidemiology, Imperial College School of Medicine, University of London, London W2 1PG,2 Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom3

Received 20 September 2001/ Returned for modification 28 December 2001/ Accepted 7 January 2002

The throat and skin of the human host are the principal reservoirs for the bacterial pathogen Streptococcus pyogenes. The emm locus encodes structurally heterogeneous surface fibrils that play numerous roles in virulence, depending on the strain. Isolates harboring the emm pattern A-C marker exhibit a strong tendency to cause throat infection, whereas emm pattern D strains are usually recovered from impetigo lesions; as a group, emm pattern E organisms fail to display obvious tissue tropisms. The peak incidence for streptococcal pharyngitis and impetigo varies with season and locale, leading to wide spatial and temporal distances between throat and skin strains. To assess any impact of niche separation on genetic variation, the extent of recombinational exchange between emm pattern A-C, D, and E subpopulations was evaluated. Analysis of nucleotide sequence data for internal portions of seven housekeeping loci from 212 isolates provides evidence of extensive recombination between strains belonging to different emm pattern subpopulations. Furthermore, no fixed nucleotide differences were found between emm pattern A-C and D strains. Thus, despite some niche separation created by distinct epidemiological trends and innate tissue tropisms there is little evidence for neutral gene divergence between throat and skin strains. Maintenance of a relationship between emm pattern and tissue tropism in the face of underlying recombination suggests that tissue tropism is associated with emm or a closely linked gene.

* Corresponding author. Mailing address: Osborn Memorial Laboratories, Yale University, 165 Prospect St., Box 208106, New Haven, CT 06520-8106. Phone: (203) 785-4480. Fax: (203) 737-4285. E-mail: debra.bessen{at}yale.edu.

Editor: E. I. Tuomanen

Infection and Immunity, April 2002, p. 1971-1983, Vol. 70, No. 4
0019-9567/02/$04.00+0     DOI: 10.1128/IAI.70.4.1971-1983.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2002 by the American Society for Microbiology. All rights reserved.