Background and Objectives: In October 2008, an investigation was conducted into a cluster of gram-negative bloodstream infections after invasive pain management procedures at an outpatient facility to identify additional cases and determine the source of illness.

Methods: We conducted a retrospective cohort study to determine exposures associated with illness. Eligible patients had an invasive procedure in the 4 days before or after the procedure date of the initial case-patients. Infection control assessments were made, and environmental specimens collected.

Results: Four laboratory-confirmed case-patients (3 with Klebsiella pneumoniae and 1 with Enterobacter aerogenes) and 5 suspect case-patients were identified. In addition to the 9 confirmed and suspect case-patients, 45 patients were interviewed. All confirmed and suspect case-patients had a sacroiliac joint steroid injection procedure; injection into the sacroiliac joint was associated with illness (9/22 versus 0/31; P < 0.0001). Multiple breaches in infection control were noted including the reuse of single-use vials for multiple patients. The 3 K. pneumoniae with positive blood cultures were indistinguishable by pulse-field gel electrophoresis, and the E. aerogenes-positive blood culture was indistinguishable by pulse-field gel electrophoresis to the culture from an open vial of 100-mL iodixanol contrast solution.

Conclusion: Infection was associated with pain management procedures, specifically those involving injection to the sacroiliac joint. Lapses in infection control likely led to the contamination of single-use vials that were then used for multiple patients. Reuse of medication vials should be restricted, and affordable single-dose vials should be made available.