Three cases of invasive meningococcal disease caused by a capsule null locus strain circulating among healthy carriers in Burkina Faso.
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.
Findlow
Helen
H
Vaccine Evaluation Unit, Health Protection Agency North West, Manchester Royal Infirmary, Manchester, M13 9WZ, UK. helen.findlow@hpa.org.uk
Vogel
Ulrich
U
Mueller
Judith E
JE
Curry
Alan
A
Njanpop-Lafourcade
Berthe-Marie
BM
Claus
Heike
H
Gray
Stephen J
SJ
Yaro
Seydou
S
Traoré
Yves
Y
Sangaré
Lassana
L
Nicolas
Pierre
P
Gessner
Bradford D
BD
Borrow
Ray
R
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
D004269:DNA, Bacterial; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides