Quality Control Test for Pathogenic Bacteria Contaminated Water

Technology No. 20180155

Unique dielectrophoresis (DEP) step improves bacterial recovery

A fast, simple and accurate quality control test can determine water quality where a very dilute level of contamination by pathogenic bacteria is suspected. The test uses a novel dielectrophoresis (DEP) step that concentrates and recovers a high fraction of bacteria. Then, inactivated free DNA from no-longer-viable bacteria allows nucleic acid amplification technology to measure DNA concentrations from only the pathogenic species. The DEP step improves bacterial recovery enough that smaller quantities of water can be used, and the unique nucleic acid primers identify specific genes of the live, pathogenic bacteria without also tagging other bacteria. This technology can be used for endoscope reprocessing quality testing: an area of particular concern due to the recent number of patient infections and deaths caused by cross-contamination of incompletely processed endoscopes.

Fast, simple and accurate quality control test

Monitoring water quality is important not only for municipal water suppliers but also in the medical field. In particular, measuring water quality of rinsate from medical instrumentation (e.g., endoscopes) can determine if a device has been cleaned adequately. A key requirement is the ability to detect small quantities of pathogens (i.e., as low as 1 CFU/mL of sample), and to do so quickly enough to determine if rinse water needs further treatment or medical devices need more cleaning. Current water tests that measure metabolic pathway components as a proxy for the presence of organisms are limited in that these markers are not specific to pathogens or viable bacteria, and the tests are not sensitive at the low levels required. Other tests that culture samples from water require a 12 to 48 hour incubation before producing results, too long a wait for many applications. This new test is fast, simple and accurate. It works with dilute levels of pathogenic bacterial contamination as well as with smaller water samples.

Phase of Development

  • Proof of concept


  • Fast, simple and accurate quality control test for water
  • Uses smaller samples of water


  • Dielectrophoresis (DEP) step improves bacterial recovery
  • Works with very dilute levels of pathogenic bacterial contamination
  • Nucleic acid amplification measures DNA concentrations from only pathogenic species


  • Measuring water quality
  • Medical instrumentation (e.g., endoscopes)
  • Municipal water suppliers
  • Endoscope reprocessing quality testing
  • Determining water safety in post-disaster, wilderness or combat settings

Satoshi Ishii, PhD
Assistant Professor, Department of Soil, Water, and Climate
External Link (www.swac.umn.edu)

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