Effects of a Disinfection Device on Colonization of Sink Drains and Patients During a Prolonged Outbreak of Multidrug-resistant Pseudomonas Aeruginosa in an Intensive Care Unit

Background: Sink drains in intensive care units (ICUs) are frequently colonized with bacteria such as Pseudomonas aeruginosa.

Aim: To study the influence of installing disinfecting devices on sink drains on colonization of sinks and patients in an ICU during a prolonged outbreak of multidrug-resistant P. aeruginosa.

Methods: From 2010, there was a clonal outbreak of multidrug-resistant P. aeruginosa (MDR-PA). In April 2013, in ICU subunit A, the siphons draining these sinks were replaced by devices applying heat and electromechanical vibration to disinfect the draining fluid. In the other units, siphons were replaced by new polyvinyl chloride plastic siphons (control). In February 2016 the disinfecting devices were also placed at ICU subunit B.

Findings: Baseline colonization rate of sinks was 51% in ICU A and 46% in ICU B. In ICU A colonization decreased to 5% (P < 0.001) after the intervention whereas it was 62% in ICU B (control). After installing the disinfection devices in ICU B, colonization rate was 8.0 and 2.4% in ICU A and B, respectively (both P < 0.001 compared with baseline). Colonization in ICU patients decreased from 8.3 to 0 per 1000 admitted patients (P < 0.001) and from 2.7 to 0.5 per 1000 admitted patients (P = 0.1) in ICU A and B respectively.

Conclusion: Colonization with MDR-PA in sink drains in an ICU was effectively managed by installing disinfection devices to the siphons of sinks. Colonization of patients was also significantly reduced, suggesting that sink drains can be a source of clinical outbreaks with P. aeruginosa and that disinfecting devices may help to interrupt these outbreaks.