Pantoea Bloodstream Infection Outbreak at an Oncology Clinic — Illinois, 2012–2013

BACKGROUND: Pantoea species are gram-negative bacteria inhabiting plants, soil, and water that uncommonly cause human infections. During August 2012–February 2013, an outpatient oncology clinic (Clinic A) identified 8 patients with Pantoea species bloodstream infections, prompting an investigation to control the outbreak. 

METHODS: Cases were defined as Pantoea species isolation from blood or catheter tip cultures of Clinic A patients during July 2012–May 2013. We reviewed Clinic A’s medical charts and laboratory records and examined infection prevention practices and the water system. Environmental samples were collected for culture. Clinical and environmental Pantoea isolates were compared by using pulsed-field gel electrophoresis (PFGE).

RESULTS: Twelve Pantoea agglomerans cases were identified; median age was 65 (range: 41–78) years. All patients had malignancies; 11/12 had indwelling vascular access. The only common exposure was receipt of intravenous infusions at Clinic A. Deficiencies in parenteral medication preparation and handling were identified (e.g., suboptimal hand hygiene, placing infusates near sinks with potential for splash-back contamination). Inspection revealed substantial dead space piping in building plumbing and inadequate chlorine residual in sink tap water. P. agglomerans were isolated from composite surface swabs of 6 separate sinks and an ice machine; the isolate from the clinic pharmacy sink (in the medication preparation area) was indistinguishable by PFGE from 7/9 available patient isolates.

CONCLUSIONS: Water system irregularities contributing to tap water contamination during parenteral medication preparation or handling likely caused these Pantoea bloodstream infections. Products compounded in this outpatient clinic propagated a health care–associated outbreak, underscoring the importance of adhering to recommended practices for medication preparation and handling. Further efforts are needed to understand the role of water system maintenance in infection prevention.