Immunochemical studies and genetic background of two Neisseria meningitidis isolates expressing unusual capsule polysaccharide antigens with specificities of both serogroup Y and W135.
We described 2 unusual Neisseria meningitidis strains isolated from epidemiologically unrelated invasive meningococcal disease cases in Ontario, Canada. Both isolates have features typical of serogroup Y N. meningitidis: are of serotype 2c, are of the multi-locus sequence types typical of the serogroup Y strains in Canada, and are genotyped as serogroup Y based on a previously described PCR-ELISA method that detects the serogroup-Y-specific siaD gene. However, both strains were poly-agglutinable in both anti-Y and anti-W135 antisera. Further studies on 1 of these 2 isolates showed the presence of glucose and galactose as well as sialic acids in its purified capsular polysaccharide, suggesting the presence of both serogroup Y and serogroup W135 polysaccharides. Rabbit antisera produced to this strain contained antibodies to both purified serogroup Y and serogroup W135 capsular polysaccharides. Absorption experiments with either serogroup Y or serogroup W135 bacteria confirmed the presence of antibodies to these 2 different polysaccharides. DNA sequencing of the cps operon from both isolates revealed a siaD gene with 99.7% homology to the published siaD sequence from a serogroup Y strain but with 3 point mutations that all resulted in amino acid changes. How these strains may affect results of routine surveillance, PCR diagnosis, and immuno-protection by vaccination are discussed.
Tsang
Raymond S W
RS
Laboratory for Vaccine Preventable Bacterial Diseases, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E3R2, Canada. raymond_tsang@phac-aspc.gc.ca
Tsai
Chao Ming
CM
Henderson
Averil M
AM
Tyler
Shaun
S
Law
Dennis K S
DK
Zollinger
Wendell
W
Jamieson
Frances
F
D019943:Amino Acid Substitution / Q000235:genetics; D000907:Antibodies, Bacterial / Q000276:immunology; D016667:Bacterial Capsules / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005690:Galactose / Q000032:analysis; D005838:Genotype; D005947:Glucose / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008589:Meningococcal Infections / Q000382:microbiology; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D009864:Ontario; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012703:Serotyping; D012794:Sialic Acids / Q000032:analysis
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012794:Sialic Acids; D005947:Glucose; D005690:Galactose