An outbreak of Serratia marcescens in two neonatal intensive care units

Outbreaks of infection in neonatal intensive care units (NICUs) due to Serr atia marcescens are well recognized. In some outbreaks no paint source has been found, whereas in others cross-infection has been associated with cont aminated ventilator equipment, disinfectants, hands and breast pumps. We re port an outbreak due to S. marcescens that involved two geographically dist inct NICUs. The outbreak occurred over a sis week period; 17 babies were co lonized, 12 at Glasgow Royal Maternity Hospital (GRMH) and five at the Quee n Mothers Hospital (QMH). At GRMH three babies developed septicaemia, of wh om two died. The outbreak isolates were of the same serotype and phage type and were indistinguishable on the basis of restriction fragment length pal ! morphism analysis. During the outbreak, two babies shown consistently to be negative on screening, were transferred between the two units. In additi on, two members of medical staff attended both units. In QMH no means of cr oss infection was identified. However, in GRMH the outbreak strain of S. ma rcescens was isolated from a laryngoscspe blade and a sample of expressed b reast milk. (C) 2000 The Hospital Infection Society.