title: Selection for phase variation of LOS biosynthetic genes frequently occurs in progression of non-typeable Haemophilus influenzae infection from the nasopharynx to the middle ear of human patients.
abstract: Surface structures in Haemophilus influenzae are subject to rapid ON/OFF switching of expression, a process termed phase variation. We analyse tetranucleotide repeats controlling phase variation in lipo-oligosaccharide (LOS) genes of H. influenzae in paired isolates from both the nasopharynx and middle ears of paediatric patients with chronic or recurrent otitis media. A change in expression of at least one of the seven phase variable LOS biosynthesis genes was seen in 12 of the 21 strain pairs. Several strains showed switching of expression in multiple LOS genes, consistent with a key role for phase variable LOS biosynthetic genes in human infection.
authors.affiliation: School of Molecular and Microbial Sciences, University of Queensland, St. Lucia, Brisbane, Queensland, Australia.
authors.forename: Kate L
authors.initials: KL
authors.lastname: Fox
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Atack
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Yogitha N
authors.initials: YN
authors.lastname: Srikhanta
authors.affiliation: School of Molecular and Microbial Sciences, University of Queensland, St. Lucia, Brisbane, Queensland, Australia.
authors.forename: Anja
authors.initials: A
authors.lastname: Eckert
authors.affiliation: Centre for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Novotny
authors.affiliation: Centre for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America.
authors.forename: Lauren O
authors.initials: LO
authors.lastname: Bakaletz
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D002648:Child; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D018450:Disease Progression; D004432:Ear, Middle / Q000382:microbiology*; D006192:Haemophilus Infections / Q000382:microbiology* / Q000473:pathology; D006193:Haemophilus influenzae / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D006801:Humans; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D009305:Nasopharynx / Q000382:microbiology*; D010033:Otitis Media / Q000382:microbiology / Q000473:pathology; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008070:Lipopolysaccharides