1 Department of Pediatrics, Georgetown University Medical Center Washington, D.C. 20007
Citrobacter is a member of the Enterobacteriaceae family presently grouped with Salmonella and Arizona. Most reported isolates of these organisms have been in adults where they have been considered as either normal bowel flora, of indeterminate clinical significance, or as secondary invaders in mixed cultures in compromised hosts. Occasionally they have been isolated in adult patients in pure cultures in urine and blood. Positive cerebrospinal fluid cultures, on the other hand, have been restricted to the newborn period as a very rare cause of neonatal meningitis.
Recently Citrobacter diversus has been recognized as a distinct species in the larger group of hydrogen sulfide-negative Citrobacter by Ewing and Davis.1