title: Identification of new genetic regions more prevalent in nontypeable Haemophilus influenzae otitis media strains than in throat strains.
abstract: Nontypeable (NT) Haemophilus influenzae strains cause significant respiratory illness and are isolated from up to half of middle ear aspirates from children with acute otitis media. Previous studies have identified two genes, lic2B and hmwA, that are associated with NT H. influenzae strains isolated from the middle ears of children with otitis media but that are not associated with NT H. influenzae strains isolated from the throats of healthy children, suggesting that they may play a role in virulence in otitis media. In this study, genomic subtraction was used to identify additional genetic regions unique to middle ear strains. The genome of NT H. influenzae middle ear strain G622 was subtracted from that of NT H. influenzae throat strain 23221, and the resultant gene regions unique to the middle ear strain were identified. Subsequently, the relative prevalence of the middle ear-specific gene regions among a large panel of otitis media and throat strains was determined by dot blot hybridization. By this approach, nine genetic regions were found to be significantly more prevalent in otitis media strains. Classification tree analysis of lic2B, hmwA, and the nine new potential otitis media virulence genes revealed two H. influenzae pathotypes associated with otitis media.
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, 109 Observatory Street, Ann Arbor, MI 48109-2029, USA.
authors.forename: Jingping
authors.initials: J
authors.lastname: Xie
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Juliao
authors.forename: Janet R
authors.initials: JR
authors.lastname: Gilsdorf
authors.forename: Debashis
authors.initials: D
authors.lastname: Ghosh
authors.forename: Mayuri
authors.initials: M
authors.lastname: Patel
authors.forename: Carl F
authors.initials: CF
authors.lastname: Marrs
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004432:Ear, Middle / Q000382:microbiology; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D005838:Genotype; D006192:Haemophilus Infections / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008824:Michigan; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010033:Otitis Media / Q000382:microbiology*; D010614:Pharynx / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C104912:lic2B protein, Haemophilus influenzae