Center for Biofilm Engineering 

Standardized Biofilm Methods
Research Area

Goal

Our goal is to develop, standardize, validate and publish methods for quantifying biofilm and assessing antibiofilm treatments for the benefit of academia, regulatory agencies and industry.

Meet the Research Team
 

Standardization

• Provides an avenue for comparing results
• Improves communication through a common vocabulary
• Tests for efficacy
• Supplies tools for teaching

Standardization is a proven way to provide convincing data for decision making. The challenge when crafting a method for estimating real world efficacy is to find the proper balance between field relevancy and practicality while achieving the statistical specifications required of a standard method. A method will not be accepted unless it is proven statistically.

The Six R's:  Statistical Hallmarks of a Standard Method

Repeatable
Independent repeats of the same experiment in the same laboratory produce nearly the same result, as indicated by a small standard deviation.

Responsive
An SOP is able to distinguish between treatments of high and low efficacy. A responsive SOP is also called sensitive.

Relevant
The method adequately models the field conditions where a disinfectant will be applied.

Rugged
Slight changes to the SOP do not result in a significantly different response from what is predicted.

Reproducible
Repeats of the same experiment run independently by different researchers in different laboratories produce nearly the same result as indicated by a small standard deviation (SD).

Reasonable
The standard operating procedure (SOP) uses equipment that is “typical” for a laboratory and does not require an excessive amount of time, supplies or highly specialized training.

Relevant Publications

DeVries, T. and M. Hamilton, 1999. "Estimating the Antimicrobial Log Reduction: Part 1. Quantitative Assays," Quantitative Microbiology, 1:29-45.

DeVries, T. and M. Hamilton, 1999. "Estimating the Antimicrobial Log Reduction: Part 2. Presence/Absence Assays," Quantitative Microbiology, 1:47-62.

Goeres, D.M., L.R. Loetterle, M.A. Hamilton, R. Murga, D.W. Kirby, and R.M. Donlan, 2005. "Statistical Assessment of a Laboratory Method for Growing Biofilms," Microbiology, 151:757-762.

Pitts, B., A. Willse, G.A. McFeters, M.A. Hamilton, N. Zelver and P.S. Stewart, 2001. "A Repeatable Laboratory Method for Testing the Efficacy of Biocides Against Toilet Bowl Biofilms," J. Appl. Microbiol., 91:110-117.

Tilt, N. and M.A. Hamilton, 1999. "Repeatability and Reproducibility of Germicide Tests: A Literature Review," J. AOAC International, 82(2):384-389.

Zelver, N., M. Hamilton, B. Pitts, D. Goeres, D. Walker, P. Sturman, and J. Heersink, 1999. "Measuring Antimicrobial Effects on Biofilm Bacteria: From Laboratory to Field," in Methods in Enzymology: Biofilms, R.J. Doyle (Ed.), Academic Press, San Diego, CA 310:608-628.

Zelver, N., M. Hamilton, D. Goeres, D. Walker, and J. Heersink, 2001. "Development of a Standardized Antibiofilm Test," in Methods in Enzymology: Microbial Growth in Biofilms Part B, R.J. Doyle (Ed.), Academic Press, New York 337:363-376.
 

For more information, email:  Dr. Marty Hamilton, Professor Emeritus of Statistics or Darla Goeres, Research Engineer.