title: Meningococcal carriage rates in healthy individuals in Japan determined using Loop-Mediated Isothermal Amplification and oral throat wash specimens.
abstract: The detailed epidemiology of meningococcal diseases in Japan has yet to be determined and, moreover, the healthy carriage rate is also unknown. In this study, to obtain insight into the carriage rate of Neisseria meningitidis in healthy individuals in Japan, we developed a new method to detect the N. meningitidis-specific ctrB gene, one of the genes encoding enzymes for capsule synthesis, by Loop-Mediated Isothermal Amplification (LAMP) and examined the meningococcal carriage rate by using self-collected oral throat wash specimens from 836 students at a university. Examination by LAMP showed that 7 out of 836 samples were positive for N. meningitidis DNA, and the results were also verified by the nested PCR method for the meningococcus specific ggt gene. The N. meningitidis carriage rate in healthy individuals was estimated to be 0.84%. Moreover, we further confirmed by the nested-PCR-based serogroup typing method that 5 of the positive samples belonged to serogroup Y, 1 belonged to group B and 1 was unidentifiable. Considering the epidemiology for meningococcal diseases in Japan, the carriage rate and the serogroup profile seem to be consistent with low incidence of meningococcal diseases and serogroup distribution of clinical meningococcal isolates in Japan, respectively.
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Healthcare Center, Hokkaido University of Education, Hokkaido, Japan.
authors.forename: Masae
authors.initials: M
authors.lastname: Haga
authors.affiliation: Department of Infectious Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Department of Infectious Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Saitoh
authors.affiliation: Department of Bacteriology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Takeru
authors.initials: T
authors.lastname: Kitahara
authors.affiliation: Department of Bacteriology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Sohkichi
authors.initials: S
authors.lastname: Matsumoto
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: ohnishi7@nih.go.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
mesh_terms: D002353:Carrier State; D005798:Genes, Bacterial; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008589:Meningococcal Infections / Q000175:diagnosis / Q000453:epidemiology*; D021141:Nucleic Acid Amplification Techniques; D010614:Pharynx / Q000382:microbiology; D016133:Polymerase Chain Reaction
keywords: Healthy carrier; Loop-Mediated Isothermal Amplification; Meningococcal diseases; Neisseria meningitidis; Oral throat wash specimens