Serratia marcescens pseudobacteraemia in neonates associated with a contaminated blood glucose/lactate analyzer confirmed by molecular typing.

Three episodes of Serratia marcescens pseudobacteraemia occurred on a neonatal intensive care unit. Following the first two cases, one full term and one pre-term infant, the source was identified as a glucose/lactate analyzer. Blood culture and environmental isolates of the organisms involved were indistinguishable when subjected to pulsed-field gel electrophoresis of Spe 1 digests and PCR ribotyping. Failure to recognize pseudobacteraemia in neonates results in inappropriate therapy for the individual and increased antibiotic pressures on the unit. Attention to the possibility of cross infection when using automated analyzers is required to minimize the risks of true or pseudoinfection to patients.