title: Pertactin negative Bordetella pertussis demonstrates higher fitness under vaccine selection pressure in a mixed infection model.
abstract: Whooping cough or pertussis is a highly infectious respiratory disease in humans caused by Bordetella pertussis. The use of acellular vaccines (ACV) has been associated with the recent resurgence of pertussis in developed countries including Australia despite high vaccination coverage where B. pertussis strains that do not express pertactin (Prn), a key antigenic component of the ACV, have emerged and become prevalent. In this study, we used an in vivo competition assay in mice immunised with ACV and in naïve (control) mice to compare the proportion of colonisation with recent clinical Prn positive and Prn negative B. pertussis strains from Australia. The Prn negative strain colonised the respiratory tract more effectively than the Prn positive strain in immunised mice, out-competing the Prn positive strain by day 3 of infection. However, in control mice, the Prn positive strain out-competed the Prn negative strain. Our findings of greater ability of Prn negative strains to colonise ACV-immunised mice are consistent with reports of selective advantage for these strains in ACV-immunised humans.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Safarchi
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Sophie
authors.initials: S
authors.lastname: Octavia
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Laurence Don Wai
authors.initials: LD
authors.lastname: Luu
authors.affiliation: Pathology and Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Chin Yen
authors.initials: CY
authors.lastname: Tay
authors.affiliation: Centre for Infectious Diseases and Microbiology-Public Health, Institute of Clinical Pathology and Medical Research-Pathology West, Westmead Hospital, New South Wales, Australia; Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, New South Wales, Australia.
authors.forename: Vitali
authors.initials: V
authors.lastname: Sintchenko
authors.affiliation: National Centre for Immunisation Research and Surveillance, Children's Hospital at Westmead and University of Sydney, New South Wales, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wood
authors.affiliation: Vaccinology and Immunology Research Trials Unit, Women's and Children's Hospital and School of Paediatrics and Reproductive Health and Robinson Research Institute, University of Adelaide, South Australia, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Marshall
authors.affiliation: National Centre for Immunisation Research and Surveillance, Children's Hospital at Westmead and University of Sydney, New South Wales, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: McIntyre
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia. Electronic address: r.lan@unsw.edu.au.
authors.forename: Ruiting
authors.initials: R
authors.lastname: Lan
mesh_terms: D000818:Animals; D001315:Australia; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology*; D001886:Bordetella pertussis / Q000254:growth & development* / Q000276:immunology* / Q000302:isolation & purification; D060085:Coinfection / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008807:Mice, Inbred BALB C; D010567:Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D012641:Selection, Genetic; D010566:Virulence Factors, Bordetella / Q000235:genetics* / Q000276:immunology*; D014917:Whooping Cough / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D010567:Pertussis Vaccine; D010566:Virulence Factors, Bordetella; C068929:pertactin
keywords: Acellular pertussis vaccine; B. pertussis; Mixed infection; Mouse model; Pertactin negative