JCM Figure table search 04
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 Sellin, M.
Right arrow Articles by Norgren, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sellin, M.
Right arrow Articles by Norgren, M.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, September 2000, p. 3420-3428, Vol. 38, No. 9
0095-1137/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Genotyping of the Capsule Gene Cluster (cps) in Nontypeable Group B Streptococci Reveals Two Major cps Allelic Variants of Serotypes III and VII

Mats Sellin,1,* Carin Olofsson,1 Stellan Håkansson,2 and Mari Norgren1

Department of Clinical Bacteriology1 and Department of Pediatrics,2 Umeå University, S-901 85 Umeå, Sweden

Received 21 December 1999/Returned for modification 29 May 2000/Accepted 12 July 2000

Forty group B Streptococcus (GBS) isolates obtained from Europe and the United States previously reported to be nontypeable (NT) by capsule serotype determination were subjected to buoyant density gradient centrifugation. From nearly half of the isolates capsule-expressing variants could be selected. For characterization of the remaining NT-GBS isolates, the capsule operon (cps) was amplified by the long-fragment PCR technique and compared by restriction fragment length polymorphism (RFLP) analysis. The patterns from serotype reference isolates (n = 32) were first determined and used as a comparison matrix for the NT-GBS isolates. Using two restriction enzymes, SduI and AvaII, cluster analysis revealed a high degree of similarity within serotypes but less than 88% similarity between serotypes. However, serotypes III and VII were each split in two distant RFLP clusters, which were designated III1 and III2 and VII1 and VII2, respectively. Among the isolates that remained NT after repeated Percoll gradient selections, two insertional mutants were revealed. Both were found in blood isolates and harbored insertion sequence (IS) elements within cpsD: one harbored IS1548, and the other harbored IS861. All other NT-GBS isolates could, by cluster analysis, be referred to different serotypes by comparison to the RFLP reference matrix. In pulsed-field gel electrophoresis of SmaI-restricted chromosomal DNA, patterns from allelic type 1 and 2 isolates were essentially distributed in separate clusters in serotypes III and VII. A covariation with insertion sequence IS1548 in the hylB gene was suggested for serotype III, since allelic type III1 harboring IS1548 in hylB, clustered separately. The variation in serotype VII was not dependent on the presence of IS1548, which was not detected at any position in the type VII chromosome.

* Corresponding author. Mailing address: Department of Clinical Bacteriology, Umeå University, S-901 85 Umeå, Sweden. Phone: 46 90 7851123. Fax: 46 90 7852225. E-mail: mats.sellin{at}climi.umu.se.

Journal of Clinical Microbiology, September 2000, p. 3420-3428, Vol. 38, No. 9
0095-1137/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Antimicrob. Agents Chemother. Clin. Microbiol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 2000 by the American Society for Microbiology. All rights reserved.