Genetic basis for nongroupable Neisseria meningitidis.
Nongroupable Neisseria meningitidis may constitute one-third or more of meningococcal isolates recovered from the nasopharynx of human carriers. The genetic basis for nongroupability was determined in isolates obtained from a population-based study in which 60 (30.9%) of 194 meningococcal isolates from asymptomatic carriers were not groupable. Forty-two percent of nongroupable isolates were related to serogroup Y ET-508/ST-23 clonal complex strains, the most common groupable carrier isolate from the study population. Nongroupable isolates were all rapidly killed by 10% normal human serum. The capsule loci of 6 of the ET-508/ST-23 complex strains and of 25 other genetically diverse nongroupable meningococci were studied in detail. Serogroup A or novel capsule biosynthesis genes were not found. Nongroupable isolates were genetically serogroup Y, B, or C isolates that did not express capsule but were related to groupable isolates found in the population (class I); capsule deficient because of insertion element-associated deletions of capsule biosynthesis genes (class II); or isolates that lacked all capsule genes and formed a distinct genetic cluster not associated with meningococcal disease (class III).
Department of Veterans Affairs Medical Center, Decatur, Georgia, USA. jdola01@emory.edu
Jennifer M
JM
Dolan-Livengood
Yoon K
YK
Miller
Larry E
LE
Martin
Rachel
R
Urwin
David S
DS
Stephens
D000293:Adolescent; D000907:Antibodies, Bacterial / Q000276:immunology; D002353:Carrier State / Q000382:microbiology; D004251:DNA Transposable Elements / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D009345:Neisseria meningitidis / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D009876:Operon / Q000235:genetics; D010802:Phylogeny; D011995:Recombination, Genetic / Q000235:genetics
D000907:Antibodies, Bacterial; D004251:DNA Transposable Elements