Hollister Hydrofera Blue Bacteriostatic Adhesive Foam Ostomy Dressing without Border 2-1/2" Dia With Moisture Retentive Film, Made From Polyvinyl Alcohol Hydrofera Blue Foam Bacteriostatic Dressings is a very unique would care dressing. It is made from PVA sponge that is infused with Gentian Violet and Methylene Blue. It is considered a dry foam dressing. Because of this it will prevent major germs like VRE and MRSA.