Bacteriophage to Combat Biofilms in Hospital Drains

Abstract

BackgroundAccording to the World Health Organization, nearly 15% of all hospitalized patients worldwide acquire nosocomial infections. A particular area of concern for bacterial build up in hospitals is sink drains. The moist, microbiologically active environment of drains promotes the formation of biofilms that are difficult to target with standard chemical disinfectants. Bacteriophages, however, show potential to be used as disinfecting agents in hospital drains. Not only do bacteriophages increase in titer as they infect, spreading to hard-to-reach surfaces, phages have been shown to degrade the extracellular matrix of biofilms and gain access to underlying bacteria. This research explores the potential of bacteriophages to eradicate biofilms in an environment modeling a sink drain by comparing the efficacy, range, and durability of bacteriophage to a chemical disinfectant.\n\nMethodsE. coli biofilms were grown in M9 minimal media placed in sink P-traps assigned one of three treatments: chemical disinfectant, bacteriophage, or deionized water (control). Biofilms were quantified at five time points -- 1, 12, 24, 36, and 48 hours -- using the crystal violet assay.\n\nResultsBoth chemical disinfectant and bacteriophage significantly decreased the optical densities of biofilms (p < 0.001***). P-traps treated with bacteriophages showed more uniform destruction of biofilm across P-trap compared to chemical disinfectant (p < 0.01**). A trend may suggest that over time bacteriophage became more effective at reducing biofilm than chemical disinfectant.\n\nConclusionThis work highlights the potential of bacteriophage as an alternative to conventional chemical disinfectants for biofilm control in settings such as hospital drains.\n\nImportanceNosocomial infections prolong hospital stay, costing the U.S. healthcare system $5-10 billion annually. An increasing number of reports demonstrate that sink drains -- reservoirs for multidrug resistant bacteria -- may be a source of hospital-related outbreaks. Recent studies have elucidated the mechanism of dispersal of bacteria from contaminated sinks to patients, but limited data are available identifying disinfecting methods for hospital drains. Not only did this study demonstrate that bacteriophages could reduce biofilms on sink drains just as effectively as a commercial disinfectant, it showed that phages tended to spread more thoroughly across P-traps and may work for longer. With hand-washing an imperative activity for disease prevention, hospital sinks should remain clean. This work explores an alternative disinfecting method for hospital sink drains.