Capsulation loci of non-serotype b encapsulated Haemophilus influenzae.


Journal Article

Invasive infections caused by non-type b encapsulated Haemophilus influenzae have increased recently. Because capsule is a major virulence factor, capsulation of 62 recently isolated non-serotype b encapsulated strains was examined. Repeated serotyping confirmed only 69.0% of isolates. The combination of slide agglutination and cap genotyping confirmed 78.9% of type a, 100% of type e, and 86.4% of type f strains. Seven nonencapsulated strains may have lost capsulation through homologous recombination. Three strains that could not be serotyped or genotyped failed to hybridize with any cap probe and are probably nontypeable H. influenzae. Of isolates that retained an intact cap locus, 62.2% had evidence of cap amplification. The epidemiology of non-type b encapsulated H. influenzae infections is complicated by the poor specificity of available serologic reagents and by spontaneous capsule loss. Recently isolated invasive non-type b encapsulated H. influenzae frequently have cap amplification, which may contribute to their virulence.

Full Text

Cited Authors

  • Ogilvie, C; Omikunle, A; Wang, Y; St Geme III, JW; Rodriguez, CA; Adderson, EE

Published Date

  • July 2001

Published In

Volume / Issue

  • 184 / 2

Start / End Page

  • 144 - 149

PubMed ID

  • 11424010

Pubmed Central ID

  • 11424010

Electronic International Standard Serial Number (EISSN)

  • 1537-6613

International Standard Serial Number (ISSN)

  • 0022-1899

Digital Object Identifier (DOI)

  • 10.1086/322001


  • eng