title: sodC-based real-time PCR for detection of Neisseria meningitidis.
abstract: Real-time PCR (rt-PCR) is a widely used molecular method for detection of Neisseria meningitidis (Nm). Several rt-PCR assays for Nm target the capsule transport gene, ctrA. However, over 16% of meningococcal carriage isolates lack ctrA, rendering this target gene ineffective at identification of this sub-population of meningococcal isolates. The Cu-Zn superoxide dismutase gene, sodC, is found in Nm but not in other Neisseria species. To better identify Nm, regardless of capsule genotype or expression status, a sodC-based TaqMan rt-PCR assay was developed and validated. Standard curves revealed an average lower limit of detection of 73 genomes per reaction at cycle threshold (C(t)) value of 35, with 100% average reaction efficiency and an average R(2) of 0.9925. 99.7% (624/626) of Nm isolates tested were sodC-positive, with a range of average C(t) values from 13.0 to 29.5. The mean sodC C(t) value of these Nm isolates was 17.6±2.2 (±SD). Of the 626 Nm tested, 178 were nongroupable (NG) ctrA-negative Nm isolates, and 98.9% (176/178) of these were detected by sodC rt-PCR. The assay was 100% specific, with all 244 non-Nm isolates testing negative. Of 157 clinical specimens tested, sodC detected 25/157 Nm or 4 additional specimens compared to ctrA and 24 more than culture. Among 582 carriage specimens, sodC detected Nm in 1 more than ctrA and in 4 more than culture. This sodC rt-PCR assay is a highly sensitive and specific method for detection of Nm, especially in carriage studies where many meningococcal isolates lack capsule genes.
authors.affiliation: Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Dolan Thomas
authors.forename: Cynthia P
authors.initials: CP
authors.lastname: Hatcher
authors.forename: Dara A
authors.initials: DA
authors.lastname: Satterfield
authors.forename: M Jordan
authors.initials: MJ
authors.lastname: Theodore
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Bach
authors.forename: Kristin B
authors.initials: KB
authors.lastname: Linscott
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Raydel
authors.initials: R
authors.lastname: Mair
authors.forename: Susanna
authors.initials: S
authors.lastname: Schmink
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Arnold
authors.forename: David S
authors.initials: DS
authors.lastname: Stephens
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Hollick
authors.forename: Ana Lucia
authors.initials: AL
authors.lastname: Andrade
authors.forename: Juliana
authors.initials: J
authors.lastname: Lamaro-Cardoso
authors.forename: Ana Paula S
authors.initials: AP
authors.lastname: de Lemos
authors.forename: Jenna
authors.initials: J
authors.lastname: Gritzfeld
authors.forename: Stephen
authors.initials: S
authors.lastname: Gordon
authors.forename: Ahmet
authors.initials: A
authors.lastname: Soysal
authors.forename: Mustafa
authors.initials: M
authors.lastname: Bakir
authors.forename: Dolly
authors.initials: D
authors.lastname: Sharma
authors.forename: Shabnam
authors.initials: S
authors.lastname: Jain
authors.forename: Sarah W
authors.initials: SW
authors.lastname: Satola
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Messonnier
authors.forename: Leonard W
authors.initials: LW
authors.lastname: Mayer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000201:enzymology* / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D013482:Superoxide Dismutase / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D013482:Superoxide Dismutase