BACKGROUND: In 2013, a neonatal intensive care unit (NICU) experienced a Pseudomonas aeruginosaoutbreak with 2 deaths. Infection control measures, water remediation, and intermittent use of point-of-use water filters followed. In September 2014, CDC was notified of additional cases. We investigated to identify risk factors and prevent further cases.
METHODS: We defined a case as the first positive P. aeruginosaculture from an NICU patient during June 2013–September 2014. We reviewed medical records from the study period, and matched 1:1 by birth weight, NICU case-patients to control-patients. We performed a case-control analysis by using conditional logistic regression with pooled matched strata adjusted for age at culture. In September 2014, we observed infection control procedures, obtained environmental cultures, and typed isolates by using pulsed-field gel electrophoresis (PFGE).
RESULTS: We identified 31 cases. Case-patients were more likely to have had a peripherally inserted central catheter (adjusted odds ratio [aOR] = 7.65; 95% confidence interval [CI] = 2.03–28.76), invasive ventilation (aOR = 8.26; 95% CI = 1.80–37.83), or exposure to water without point-of-use filters (aOR = 48.14; 95% CI = 9.49–∞) £7 days before culture. We observed deficiencies in hand hygiene. Of 45 environmental samples, 31 (69%) produced P. aeruginosa; 94% of these were water-related. Isolates from the 2 most recent case-patients were indistinguishable by PFGE from water-related samples obtained from the case-patients’ rooms.
CONCLUSIONS: This P. aeruginosa outbreak was attributed to contaminated water. Inadequate hand hygiene might have contributed to higher risk for transmission to neonates with invasive devices. Point-of-use filters might be effective in preventing P. aeruginosa cases. Further water-system remediation, continuous use of point-of-use filters, and optimal hand hygiene were recommended.