OUTBREAK OF PSEUDOMONAS-FLUORESCENS BACTEREMIA AMONG ONCOLOGY PATIENTS

From 7 to 24 March 1997, four patients developed Pseudomonas fluoresce ns bacteremia at the hospital; one on the oncology ward and the other three in the chemotherapy room. These patients all had underlying mali gnancies and had the Port-A-Cath (Smiths Industries Medical Systems, D eltec, Inc., St. Paul, Minn,) implants. Three patients had primary bac teremia, and one had Port-A-Cath-related infection. None of these pati ents had received a blood transfusion before the episodes of bacteremi a, All patients recovered: two received antimicrobial agents with in v itro activity against the isolates, and the other two did not have any antibiotic treatment, A total of eight blood isolates mere recovered from these patients during the febrile episodes that occurred several minutes after the infusion of chemotherapeutic agents via the Port-A-C ath, These isolates were initially identified as P. fluorescens or Pse udomonas putida (four), Burkholderia (Ralstonia) pickettii (three), an d a non-glucose-fermenting gram-negative bacillus (one) by routine bio chemical methods and the Vitek GNI card. These isolates were later ide ntified as P. fluorescens on the basis of the characteristic cellular fatty acid chromatogram and the results of supplemental biochemical te sts. The identification of identical antibiotypes by the E test and th e random amplified polymorphic DNA patterns generated by arbitrarily p rimed PCR of the isolates showed that the outbreak was caused by a sin gle clone of P. fluorescens. Surveillance cultures of the possibly con taminated infusion fluids and disinfectants, which were performed 7 da ys after recognition of the last infected patient, failed to isolate P . fluorescens. This report of a small outbreak caused by P. fluorescen s suggests that timely, accurate identification of unusual nosocomial pathogens is crucial for early initiation of an epidemiological invest igation and timely control of an outbreak.