Contaminated lithium heparin bottles as a source of pseudobacteraemia due to Pseudomonas fluorescens

Pseudobacteraemia might be responsible for up to 50% of all positive blood cultures and its early recognition is important in order to avoid unnecessary treatment with antibiotics and delay in the search for the true cause of the fever. We describe pseudobacteraemia outbreak of Pseudomonas fluorescens related to contaminated lithium heparin bottles in a paediatric ward. Twelve patients were involved in this outbreak from December 1996-January 1997. All patients had no clinical evidence of sepsis, nevertheless most children were treated with antibiotics. Blood collection bottles were suspected as source of pseudobacteraemia and only lithium heparin bottles were found to be contaminated with P. fluorescencs indistinguishable from the blood isolates taken from these children. Withdrawal of these bottles led to the termination of the pseudobacteraemia. Following discussion with the manufacturer, the contaminated batch of lithium heparin bottles was sent back for testing, and replaced with bottles containing dried lithium heparin. A hazard report was sent to the Medical Devices Agency (MDA). In order to minimize the possibility of this problem occurring again, the manufacturer has informed MDA that all lithium heparin solution is to be filtered to 0.2 microns prior to issue, in order to minimize bacterial contamination. Continued monitoring after the pseudobacteraemia showed no isolates of P. fluorescens from the blood of paediatric patients.