title: Three cases of invasive meningococcal disease caused by a capsule null locus strain circulating among healthy carriers in Burkina Faso.
abstract: During reinforced surveillance of acute bacterial meningitis in Burkina Faso, meningococcal strains of phenotype NG:NT:NST were isolated from cerebrospinal fluid samples from 3 patients. The strains were negative for the ctrA gene but were positive for the crgA gene. Molecular typing revealed that the strains harbored the capsule null locus (cnl) and belonged to the multilocus sequence type (ST)-192. PorA sequencing showed that all strains were either P1.18-11,42; P1.18,42-1; P1.18-11,42-1; P1.18-11,42-3; or P1.18-12,42-1. Sequencing also showed that all strains were negative for the FetA receptor gene. Serum killing assays showed these strains to be resistant, with the resistance comparable with that of a fully capsular serogroup B strain, MC58. The same strains were found in 14 healthy carriers in the general population of Bobo-Dioulasso (100% of ST-192 isolates tested for cnl). The presence of cnl meningococci that can escape serum killing and cause invasive disease is of concern for future vaccination strategies and should promote rigorous surveillance of cnl meningococcal disease.
authors.affiliation: Vaccine Evaluation Unit, Health Protection Agency North West, Manchester Royal Infirmary, Manchester, M13 9WZ, UK. helen.findlow@hpa.org.uk
authors.forename: Helen
authors.initials: H
authors.lastname: Findlow
authors.forename: Ulrich
authors.initials: U
authors.lastname: Vogel
authors.forename: Judith E
authors.initials: JE
authors.lastname: Mueller
authors.forename: Alan
authors.initials: A
authors.lastname: Curry
authors.forename: Berthe-Marie
authors.initials: BM
authors.lastname: Njanpop-Lafourcade
authors.forename: Heike
authors.initials: H
authors.lastname: Claus
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gray
authors.forename: Seydou
authors.initials: S
authors.lastname: Yaro
authors.forename: Yves
authors.initials: Y
authors.lastname: Traoré
authors.forename: Lassana
authors.initials: L
authors.lastname: Sangaré
authors.forename: Pierre
authors.initials: P
authors.lastname: Nicolas
authors.forename: Bradford D
authors.initials: BD
authors.lastname: Gessner
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
mesh_terms: D000293:Adolescent; D016667:Bacterial Capsules / Q000235:genetics*; D002353:Carrier State; D002555:Cerebrospinal Fluid / Q000382:microbiology; D002648:Child; D004269:DNA, Bacterial / Q000032:analysis; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D008589:Meningococcal Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology / Q000635:transmission; D009345:Neisseria meningitidis / Q000145:classification* / Q000302:isolation & purification / Q000648:ultrastructure; D016133:Polymerase Chain Reaction
chemical_list: D004269:DNA, Bacterial; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides