uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Intra- and interstrain differences of virulence among nontypeable Haemophilus influenzae strains
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
1998 (English)In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, Vol. 106, no 9, 858-868 p.Article in journal (Refereed) Published
Abstract [en]

Nontypeable Haemophilus influenzae (NTHi) is sometimes the causative agent of invasive diseases, and it has been suggested that there may be differences in virulence among NTHi strains. Whilst studying clinical isolates of NTHi in a rat model of acute otitis media, intra- and interstrain differences in virulence were observed. Two strains with suddenly reduced capacity to cause middle ear infections and one highly virulent strain with dose requirements comparable only to encapsulated H. influenzae strains were further investigated, together with 15 other H. influenzae strains. The strains were characterized by analyzing the lipopolysaccharide, the outer membrane proteins, the hemagglutinating ability, and the polymerase chain reaction products after amplification of a gene sequence associated with encapsulation. The pathogenic capacity was assessed in two different in vivo models. It was found that the two strains with reduced pathogenic capacity could regain their virulence after animal passage. The LPS analysis and the results from the chicken embryo model suggested that the observed change in virulence might be associated with the lipopolysaccharide. For the non-animal-passaged strain 3655 there were indications that an undefined factor(s) contributed to its relatively potent virulence. As all three strains lacked genes necessary for encapsulation, in no case could any part of the increased virulence be attributed to the expression of small amounts of capsule.

Place, publisher, year, edition, pages
1998. Vol. 106, no 9, 858-868 p.
Keyword [en]
Animals, Antibodies; Monoclonal, Bacterial Outer Membrane Proteins/analysis, Bacterial Proteins/genetics, Chick Embryo, Disease Models; Animal, Enzyme-Linked Immunosorbent Assay, Haemophilus Infections/*microbiology, Haemophilus influenzae/genetics/immunology/*pathogenicity, Hemadsorption, Lipopolysaccharides/*analysis/immunology, Male, Mice, Otitis Media/*microbiology, Polymerase Chain Reaction, Rats, Rats; Sprague-Dawley, Research Support; Non-U.S. Gov't, Serial Passage, Species Specificity, Virulence
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-83419PubMedID: 9808412OAI: oai:DiVA.org:uu-83419DiVA: diva2:111327
Available from: 2006-11-02 Created: 2006-11-02Bibliographically approved

Open Access in DiVA

No full text

Other links


Search in DiVA

By author/editor
Melhus, Åsa
By organisation
Department of Medical Sciences
In the same journal
Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS)
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 136 hits
ReferencesLink to record
Permanent link

Direct link