Bacterial viability on metallic fomites

Abstract

The study measures the survival rates of vancomycin-resistant Enterococcus Jaecalis, methicillin- resistant Staphylococcus aureus, and Escherichia coli strain 0157:H7 on copper, steel, aluminum, and brass compared to the organisms' survival rate on non-metallic surfaces including glass and plastic. With increased prevalence of hospital acquired infections from antibiotic resistant or highly pathogenic organisms comes a greater importance to find means of lessening the possibility of survival of these organisms on high touch surfaces throughout the hospital. This data offers insight into whether the material of high touch surfaces makes a difference in the viability of problematic organisms in unsuspecting, yet communal places. The procedural set up consists of an inoculation of 50 uL of a 0.5 McFarland standard TSB suspension which mimics a droplet of contaminated fluid. Each droplet is inoculated onto an individual square, representing a single day period, of a grid system that divides the surfaces. The end point of survival is the point at which growth ceases upon the reconstitution of the droplet onto artificial growth media. CHROMagar is used to visually differentiate the organisms by color and rule out any possible misidentification of contamination from the environment or mishandling. This study produces a visual image of how long the bacteria survive and how much bacteria survived at what points in the course of the trial. The organisms have demonstrated significantly shorter survival times on copper and brass compared to other surfaces suggesting that these materials might be preferentially utilized for high touch surfaces.