Isolates of Neisseria meningitidis from different sites in the same patient: phenotypic and genomic studies, with special reference to adherence, piliation, and DNA restriction endonuclease pattern.

Neisseria meningitidis was isolated from the throat, blood, and cerebrospinal fluid of six patients and from the throat and blood of two patients. All 22 isolates were of serogroup B, serotype 15, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis type IV. Isolates from a single patient always possessed identical DNA restriction endonuclease patterns; this observation strongly suggested genomic identity. In spite of this apparent genomic identity, however, significant differences in piliation and adherence were observed among isolates from different sites in the same patient. Isolates from the throat were significantly more piliated (P less than .001) and adhered to human buccal epithelial cells in vitro in significantly higher numbers (P less than .001) than did isolates from the blood and the cerebrospinal fluid of the same patient. These results indicate that phase shift occurs in N. meningitidis in vivo.