Pseudomonas aeruginosa outbreak linked to sink drainage design

BackgroundThis paper describes an outbreak of Pseudomonas aeruginosa (PAE) that occurred in a haematology ward between 8 January and 24 March 2009. Four patients had healthcare-associated infections due to PAE which was recovered in the groin, blood and perianal tissue.AimThis report highlights the risks associated with the use of sinks and outlines the approach used to manage the outbreak.MethodsSubsequent investigations showed that a contaminated sink drainage system represented the possible source of spread. Of a total of 21 environmental samples taken, two samples from the sink drainage system showed a similar susceptibility pattern as the patients involved in the outbreak. Four cycles of disinfection of the sink drainage systems were attempted with various modalities.FindingsPAE contamination of the sink drains at the multiple grooves in the drains proved difficult to disinfect adequately, despite using several cleaning protocols. The outbreak was finally terminated following a change in the sink drainage system to one without grooves, hence preventing any further PAE colonisation.ConclusionOur experience demonstrated that the design of the sink drainage system may be a potential source of PAE contamination for an immunocompromised patient.