Identification of Burkholderia mallei and Burkholderia pseudomallei adhesins for human respiratory epithelial cells

BMC Microbiology

Research Article

Rachel Balder¹  Eric R Lafontaine¹  Robert J Hogan¹  William Grose²  Serena Lipski³  Ronald M Wooten³  John J Lazarus³  Donald E Woods⁴ 

[1] Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, 30602, Athens, GA, USA;Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, 30602, Athens, GA, USA;Department of Medical Microbiology and Immunology, University of Toledo Health Sciences Campus, 3055 Arlington Avenue, 43614, Toledo, OH, USA;Department of Medical Microbiology and Immunology, University of Toledo Health Sciences Campus, 3055 Arlington Avenue, 43614, Toledo, OH, USA;Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, 3330 Hospital Drive, T2N 4N1, NW Calgary, Alberta, Canada;

关键词: Normal Human Bronchial Epithelium;    Melioidosis;    Burkholderia Pseudomallei;    Double Mutant Strain;    Passenger Domain;   

DOI  :  10.1186/1471-2180-10-250

 received in 2010-08-07, accepted in 2010-09-28,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundBurkholderia pseudomallei and Burkholderia mallei cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which B. pseudomallei and B. mallei adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms.ResultsComparative sequence analyses identified a gene product in the published genome of B. mallei strain ATCC23344 (locus # BMAA0649) that resembles the well-characterized Yersinia enterocolitica autotransporter adhesin YadA. The gene encoding this B. mallei protein, designated boaA, was expressed in Escherichia coli and shown to significantly increase adherence to human epithelial cell lines, specifically HEp2 (laryngeal cells) and A549 (type II pneumocytes), as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, disruption of the boaA gene in B. mallei ATCC23344 reduced adherence to all three cell types by ~50%. The genomes of the B. pseudomallei strains K96243 and DD503 were also found to contain boaA and inactivation of the gene in DD503 considerably decreased binding to monolayers of HEp2 and A549 cells and to NHBE cultures.A second YadA-like gene product highly similar to BoaA (65% identity) was identified in the published genomic sequence of B. pseudomallei strain K96243 (locus # BPSL1705). The gene specifying this protein, termed boaB, appears to be B. pseudomallei-specific. Quantitative attachment assays demonstrated that recombinant E. coli expressing BoaB displayed greater binding to A549 pneumocytes, HEp2 cells and NHBE cultures. Moreover, a boaB mutant of B. pseudomallei DD503 showed decreased adherence to these respiratory cells. Additionally, a B. pseudomallei strain lacking expression of both boaA and boaB was impaired in its ability to thrive inside J774A.1 murine macrophages, suggesting a possible role for these proteins in survival within professional phagocytic cells.ConclusionsThe boaA and boaB genes specify adhesins that mediate adherence to epithelial cells of the human respiratory tract. The boaA gene product is shared by B. pseudomallei and B. mallei whereas BoaB appears to be a B. pseudomallei-specific adherence factor.

【 授权许可】

Unknown   
© Balder et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.