Multidrug-resistant E. Coli Outbreak in a neonatal intensive care unit (NICU)

Abstract

BACKGROUND: In August 2004, infection control identified six neonates with E. coli, all located in Section A of the medical center's 30-bed NICU. Initial investigation revealed that four of the six patients had multidrug-resistant (MDR) strains (two with nosocomial colonization in the respiratory tract, two with nosocomial bacteremia; one patient with bacteremia developed meningitis with MDR E. coli). Of the remaining two patients, both had antibiotic-sensitive strains of E. coli in blood specimens, while one had an MDR E. coli in a respiratory sample. Five of six patients weighed 1500g or less. Data indicated a rise in patient days of 33% in August, as compared to the average monthly patient days in the first 6 months of 2004. No significant changes to nursing staffing levels occurred during 2004. METHODS: Immediate actions: Surveillance cultures of all patients (rectal, tracheal, groin, umbilical); segregation of E. coli -positive neonates in isolettes on one side of NICU-A; designated staff assigned to E. coli -positive neonates; unit closed to new admissions; and strict compliance with proper handwashing. Additional interventions: once-daily surgical scrub (4% chlorhexidine); use of a gown for all healthcare workers having direct patient contact; strict enforcement of policy prohibiting artificial nails; proper cleaning of stethoscopes; environmental cultures of equipment and procedure carts; terminal cleaning of the NICU sections (including shelves, telephones, sinks). RESULTS: DNA typing using pulsed-field gel electrophoresis (PFGE) revealed that all MDR E. coli strains were related; conversely, the drug-sensitive strains had a unique PFGE pattern. One resuscitation bag and one procedure cart were positive for the MDR E. coli strain. The isolate identified from the cart was identified as being of an indistinguishable pattern from the MDR strains obtained from the neonates. No additional cases of E. coli were identified. No direct source of the organism was identified, whether having originated from a parent or healthcare worker. CONCLUSIONS: In the absence of a direct source, a comprehensive plan addressing both immediate actions and long-range solutions is often necessary to prevent continued occurrences during an outbreak situation. Equipment contaminated with the causative organism is an area of concern as this may have contributed to transfer of the organism during the outbreak. Whether a rising ratio of patients to staff may have been a contributing factor needs further investigation.