|Balajee, S - CDC, ATLANTA, GA|
|Tay, Sun - UNIV OF MALAYA, MALAYSIA|
|Lasker, Brent - CDC, ATLANTA, GA|
|Hurst, Steve - CDC, ATLANTA, GA|
Submitted to: Eukaryotic Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 30, 2007
Publication Date: June 15, 2007
Citation: Balajee, S.A., Tay, S.T., Lasker, B.A., Hurst, S.F., Rooney, A.P. 2007. Characterization of a novel gene for strain typing reveals substructuring of Aspergillus fumigatus across North America. Eukaryotic Cell. 6(8):1392-1399. Interpretive Summary: This manuscript describes research on Aspergillus fumigatus, an important fungal pathogen of humans, domestic livestock and poultry. Specifically, this study addresses an important problem in A. fumigatus epidemiology: the lack of an effective genetic typing system that can detect and differentiate distinct A. fumigatus outbreak strains. Our results show that the cell surface protein gene Afu3g08990 is capable of detecting distinct A. fumigatus outbreak strains. Our findings carry important ramifications for the diagnosis of A. fumigatus disease and for efforts aimed at A. fumigatus disease surveillance and source-tracking.
Technical Abstract: Fifty five epidemiologically linked Aspergillus fumigatus isolates obtained from six nosocomial outbreaks of invasive aspergillosis were sub-typed by sequencing the polymorphic region of the gene encoding a putative cell surface protein, Afu3g08990 (denoted as CSP). Comparative sequence analysis showed that genetic diversity was generated in the coding region of this gene by both tandem repeats and point mutations. Each unique sequence in an outbreak cluster was assigned an arbitrary number or CSP sequence type. The CSP typing method was able to identify ‘clonal’ and genotypically distinct A. fumigatus isolates and results were concordant with another discriminatory genotyping technique, the Afut1 RFLP typing method. The novel single locus sequence typing (CSP typing) strategy appears to be a simple, rapid, discriminatory tool that can be readily shared across laboratories. In addition, we found that A. fumigatus is substructured into multiple CSP phylogenetic lineages, the basis for which may be immunogenic in nature. Furthermore, we found that the A. fumigatus isolate Af293, whose genome has been sequenced, possesses a CSP gene structure that is substantially different from the other A. fumigatus strains studied here, highlighting the need for further taxonomic study.