Epidemiological investigation of Ochrobactrum anthropi strains isolated from a haematology unit

Ochrobactrum anthropi is an oxidase-producing gram-negative bacillus preferring aqueous environments. It is an opportunist of low pathogenicity with a wide and unpredictable antibiotic resistance. We observed bacteraemia caused by this organism in two immunocompromized patients hospitalized in the same haematology unit and catheter-associated sepsis was recognized within two days. Another isolate was obtained from the stools of a third patient of the same unit. Environmental investigations recovered an isolate from a tap-water sample of the unit. Pulsed-field gel electrophoresis analysis of these four isolates and two others isolates previously found in the same ward, showed identical restriction patterns for the two blood isolates and confirmed that the two bacteraemia were epidemiologically related.