289 Containment of two Outbreaks of Serratia Marcescens in a Northern Italy NICU

Abstract

S. marcescens is a recognized nosocomial pathogen especially in NICU. We describe the course and related measures of containment of two outbreaks (I-II) of S. marcescens in a 30-bed NICU. Two patients developed sepsis by S. marcescens in June 2003 following this active surveillance was established to detect infected/colonized patients and the source of the outbreak. During the outbreak period the NICU remained open to new admissions. Infected and colonized patients were cohorted in an infected area. Hygienic measures were strictly enforced for unit staff and visitors. All infants received probiotics daily. Isolates were genotyped with Pulsed Field Gel Electrophoresis (PFGE) protocol. Colonized patients were not treated with antibiotics and were discharged soon. In the period June-August 2003, 54 newborns were screened for S. marcescens, 17 (31%) infants were found colonized by S. marcescens in the digestive tract. In the same period 2 colonized patients developed sepsis from different germs (SGB, Candida albicans). In June 2004, 10 months after the first outbreak, a new fatal case of S.marcescens sepsis occurred in a VLBW in the same NICU. The following control measures revealed three (9%) colonized neonates in the Unit. By PFGE typing we identified one epidemic clone (A) in 15 infants plus the index case and two other unrelated clone (B-C) in 2 patients in outbreak I. In outbreak II one epidemic clone (D) in 3 infants and an unrelated clone in an other patient were identified. The comparative PFGE analysis excluded any relationship between the first and the second episode of sepsis and confirmed that S. marcescens was not endemic. After 6 and 2 weeks respectively the outbreaks were eradicated without any recurrence. The administration of probiotics and avoiding unnecessary exposure to antibiotics may have played an important role in the containment of the outbreak