Down the Drain: A Systematic Review of Molecular Biology Evidence Linking Sinks with Bacterial Healthcare-Associated Infections in Intensive Care Units

Abstract

This systematic review aimed to sum up the evidence gathered by molecular biology methods on the transmission of bacterial clones from sinks/sink drains environmental sources to intensive care unit (ICU) patients. Forty-five reports meeting inclusion/exclusion criteria were identified. Most were retrospective cohort studies on Gram negative multidrug resistant bacteria, with P. aeruginosa and S. marcescens being the most frequent species (26.7% and 17.8% of the studies, respectively). The reports using pulse field gel electrophoresis were the most numerous (44.4%) and found a common clone between clinical and sink/sink drains isolates in 80% of the cases. Over the last 5 years, the use of whole genome sequencing became more frequent and linked sink/sink drains isolates to clinical ones in 50% of the cases. Precise positivity timelines mostly pointed towards a patient-to-sink/sink drain transmission while only 8 reports provided back up for the sink/sink drain-to-patient. To better appraise the role of sinks/sink drains as a reservoir for nosocomial acquisition of bacteria in ICU, future reports should strive to give a precise timeline for the retrieval of isolates as well as the cut-off criteria used to assign isolates to a given clone (information lacking in 66.7% and 42.2% of the studies, respectively).