Reduction of Gordonia terrae Biofilms by Host-Specific Bacteriophage

Reduction of Gordonia terrae Biofilms by Host-Specific Bacteriophage Audrey Waits and Indiren Pillay Biofilms are protective coatings that bacterial communities produce using extracellular polymeric substances (EPS). Biofilms may form on a variety of surfaces, including water system pipes, living tissue, and indwelling medical devices. From a public health perspective, biofilms can pose a significant challenge. Because the biofilm is hydrophobic and highly selective in what substances are permitted through the EPS matrix, catheter-related infections caused by biofilms can be especially difficult to treat with antibiotics. In this study, we demonstrate that Gordonia terrae biofilms could be significantly decreased when exposed to a host-specific bacteriophage named Waits. Gordonia terrae are Gram-positive bacteria, that have been detected in rare cases on long-term catheters in severely immune-compromised patients. Biofilms of G. terrae were created on sterile medical-grade silicon discs. Once the biofilm was formed, each disc was sonicated to disrupt the biofilms, so that CFU/disc (colony forming units) could be determined as the average bacterial count on the biofilms. Once the average bacterial count was determined, the effectiveness of bacteriophage “Waits” to remove the biofilm was tested. An MOI (multiplicity of infection) of 10 was used to infect the biofilms. Biofilms were exposed to phage for 48 hours before dilution plating was done to determine how many bacterial cells remained on the discs. Comparing average bacterial counts on the silicon discs without phage versus with phage revealed a 99% decrease in bacterial counts. Based on this data, Gordonia–specific phage Waits is extremely effective at reducing Gordonia terrae biofilms on medical grade silicon discs