This Article Full Text Full Text (PDF) Other Versions of this Article: JB.01963-07v1 190/12/4313    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Google Scholar Articles by Sheets, A. J. Articles by St. Geme, J. W. PubMed PubMed Citation Articles by Sheets, A. J. Articles by St. Geme, J. W., III

 Previous Article  |  Next Article 

Journal of Bacteriology, June 2008, p. 4313-4320, Vol. 190, No. 12
0021-9193/08/$08.00+0     doi:10.1128/JB.01963-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Identification of a Novel Trimeric Autotransporter Adhesin in the Cryptic Genospecies of Haemophilus

Departments of Pediatrics,¹ Molecular Genetics and Microbiology,² Pathology, Duke University Medical Center, Children's Health Center, Durham, North Carolina 27710³

Received 17 December 2007/ Accepted 8 April 2008

Haemophilus biotype IV strains belonging to the recently recognized Haemophilus cryptic genospecies are an important cause of maternal genital tract and neonatal systemic infections and initiate infection by colonizing the genital or respiratory epithelium. To gain insight into the mechanism of Haemophilus cryptic genospecies colonization, we began by examining prototype strain 1595 and three other strains for adherence to genital and respiratory epithelial cell lines. Strain 1595 and two of the three other strains demonstrated efficient adherence to all of the cell lines tested. With a stably adherent variant of strain 1595, we generated a Mariner transposon library and identified 16 nonadherent mutants. All of these mutants lacked surface fibers and contained an insertion in the same open reading frame, which encodes a 157-kDa protein designated Cha for cryptic haemophilus adhesin. Analysis of the predicted amino acid sequence of Cha revealed the presence of an N-terminal signal peptide and a C-terminal domain bearing homology to YadA-like and Hia-like trimeric autotransporters. Examination of the C-terminal 120 amino acids of Cha demonstrated mobility as a trimer on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the capacity to present the passenger domain of the Hia trimeric autotransporter on the bacterial surface. Southern analysis revealed that the gene that encodes Cha is conserved among clinical isolates of the Haemophilus cryptic genospecies and is absent from the closely related species Haemophilus influenzae. We speculate that Cha is important in the pathogenesis of disease due to the Haemophilus cryptic genospecies and is in part responsible for the apparent tissue tropism of this organism.

Published ahead of print on 18 April 2008.