Burkholderia cepacia infections associated with intrinsically contaminated ultrasound gel: the role of microbial degradation of parabens.

OBJECTIVE: To describe an outbreak of serious nosocomial Burkholderia cepacia infections occurring after transrectal prostate biopsy associated with ultrasound gel intrinsically contaminated with paraben-degrading microorganisms.
METHODS: A retrospective chart review prompted by a blood culture isolate of B. cepacia. Identification of microorganisms in ultrasound gel in two Canadian centers and characterization by pulsed-field gel electrophoresis and assays for paraben degradation.
SETTING: Two Canadian university-affiliated, tertiary-care centers in Newfoundland and Alberta.
RESULTS: Six serious B. cepacia infections were identified at the two centers. Isolates of B. cepacia recovered from the blood of patients from both centers and the ultrasound gel used during the procedures were identical, confirming intrinsic contamination. Strains of Enterobacter cloacae isolated from ultrasound gel at the two centers were also identical. The ability to degrade parabens was proven for both B. cepacia and E. cloacae strains recovered from the ultrasound gel.
CONCLUSIONS: Ultrasound gel is a potential source of infection. Contamination occurs at the time of manufacture, with organisms that degrade parabens, which are commonly used as stabilizing agents. There are far-reaching implications for the infection control community.