An in vitro bacterial surface migration assay underneath sterile barrier material commonly found in a hospital setting.

ABSTRACT

OBJECTIVE: To determine what barrier material used in hospital neonatal intensive care units most effectively blocks bacterial migration. STUDY DESIGN: Bacterial migration distance was compared across simple and complex solid media using Escherichia coli, an early and common neonatal gut colonizer, and Staphylococcus aureus, a common skin bacterium, across polystyrene, medical-grade silicone, hydrocolloid dressing and transparent film dressing as barrier materials on complex solid media. RESULTS: Bacterial migration was significantly greater on complex versus simple solid media. Bacteria migrated farthest beneath hydrocolloid dressing and transparent film dressing, while migration underneath polystyrene and medical-grade silicone was generally comparable to no barrier. CONCLUSIONS: Commonly used hydrocolloid dressing and transparent film dressing surprisingly increases bacterial migration, possibly by providing a wet capillary surface for bacteria to attach to or inducing biofilm formation. Using polystyrene or silicone to interface with the site of catheter insertion may best avoid a bacterial wicking phenomenon.