Characterization of Citrobacter diversus strains causing neonatal meningitis.

We studied 17 strains of Citrobacter diversus isolated from the cerebrospinal fluid of infants with meningitis and compared these strains with 21 strains isolated from other body sites. The two groups of strains were similar with respect to biotype, piliation, hemolysin production, and resistance to the killing effects of serum. By using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we found that 14 (82%) of 17 strains from cerebrospinal fluid, but only two (10%) of 21 strains isolated from other body sites, possessed a minor outer membrane protein with a molecular weight of 32,000 (P less than .0001). This protein may serve as a marker for strains of C. diversus that are likely to cause meningitis or brain abscess in human neonates.