Association between Pseudomonas aeruginosa positive water samples and healthcare-associated cases: nine-year study at one university hospital

Objective: To study the association between the results of water samples and Pseudomonas aeruginosa healthcare-associated cases in a French university hospital. Methods: Generalized Estimating Equations were used on complete case and imputed datasets. The spatial unit was the building and the time unit was the quarter. Results: For the period 2004-2013, 2932 water samples were studied; 17% were positive for P. aeruginosa. A higher incidence of P. aeruginosa cases was associated with a higher proportion of positive water samples (P = 0.056 in complete case analysis and P = 0.031 with the imputed dataset). The association was no longer observed when haematology and intensive care units were excluded, but was significant in analyses of data concerning intensive care units alone (P< 0.001). Conclusion: This study suggests that water outlet contamination in hospitals can lead to an increase in healthcare-associated P. aeruginosa cases in wards dealing with susceptible patients, but does not play a significant role in other wards. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.