title: Optimization of Molecular Approaches to Genogroup Neisseria meningitidis Carriage Isolates and Implications for Monitoring the Impact of New Serogroup B Vaccines.
abstract: The reservoir for Neisseria meningitidis (Nm) is the human oropharynx. Implementation of Nm serogroup C (NmC) glycoconjugate vaccines directly reduced NmC carriage. Prophylactic vaccines are now available to prevent disease caused by the five major Nm disease causing serogroups (ABCWY). Nm serogroup B (NmB) vaccines are composed of antigens that are conserved across Nm serogroups and therefore have the potential to impact all Nm carriage. To assess the effect of these vaccines on carriage, standardized approaches to identify and group Nm are required. Real-time PCR (rt-PCR) capsule grouping assays that were internally controlled to confirm Nm species were developed for eight serogroups associated with carriage (A, B, C, E, W, X, Y and Z). The grouping scheme was validated using diverse bacterial species associated with carriage and then used to evaluate a collection of diverse Nm carriage isolates (n=234). A scheme that also included porA and ctrA probes was able to speciate the isolates, while ctrA also provided insights on the integrity of the polysaccharide loci. Isolates were typed for the Nm vaccine antigen factor H binding protein (fHbp), and were found to represent the known diversity of this antigen. The porA rt-PCR yielded positive results with all 234 of the Nm carriage isolates. Genogrouping assays classified 76.5% (179/234) of these isolates to a group, categorized 53 as nongenogroupable (NGG) and two as mixed results. Thirty seven NGG isolates evidenced a disrupted capsular polysaccharide operon judged by a ctrA negative result. Only 28.6% (67/234) of the isolates were serogrouped by slide agglutination (SASG), highlighting the reduced capability of carriage strains to express capsular polysaccharide. These rt-PCR assays provide a comprehensive means to identify and genogroup N. meningitidis in carriage studies used to guide vaccination strategies and to assess the impact of novel fHbp containing vaccines on meningococcal carriage.
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rojas
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Johanna
authors.initials: J
authors.lastname: Hoyos
authors.affiliation: School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Oldfield
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Philip
authors.initials: P
authors.lastname: Lee
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Mike
authors.initials: M
authors.lastname: Flint
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: C Hal
authors.initials: CH
authors.lastname: Jones
authors.affiliation: School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Dlawer A A
authors.initials: DA
authors.lastname: Ala'Aldeen
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.affiliation: Vaccine Research and Development, Pfizer Inc, Pearl River, New York, United States of America.
authors.forename: Annaliesa S
authors.initials: AS
authors.lastname: Anderson
mesh_terms: D006801:Humans; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000276:immunology*; D038541:Neisseria meningitidis, Serogroup B / Q000235:genetics / Q000302:isolation & purification*; D038542:Neisseria meningitidis, Serogroup C / Q000235:genetics / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D022401:Meningococcal Vaccines