Bacillus-based biocontrol strategy for Pseudomonas aeruginosa–contaminated intensive care unit sink drains: a proof-of-concept study

BACKGROUND: Hospital-acquired infections (HAIs) are a major cause of morbidity and mortality, particularly among critically ill patients. In intensive care units (ICUs), sink drains, and their associated microbiota are recognized as important reservoirs of pathogenic bacteria contributing to HAI through retrograde contamination of the environment and subsequently the patients. An approach to control sink drain contamination that is effective, easy to implement, cost-effective, environmentally sustainable, and long lasting remains challenging despite several strategies available. METHODS: This proof-of-concept study evaluated the efficacy of a Bacillus-based biocontrol strategy of 20 sink traps contaminated with Pseudomonas aeruginosa over a 12-week period. Twenty sinks located in the ICU were included and allocated to one of the three intervention groups: (i) sink trap replacement only; (ii) sink trap replacement plus application of the Bacillus-based formulation; and (iii) application of the Bacillus-based formulation only. RESULTS: Persistent contamination with P. aeruginosa was observed in all three intervention groups throughout the duration of the study using a qualitative culture approach. CONCLUSIONS: Although Bacillus-based biocontrol approaches have demonstrated possible efficacy on dry surfaces, this study could not show any effect of a Bacillus-based biocontrol strategy on the P. aeruginosa contamination of ICU sink traps.