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FDA approves marketing of test for medical steam device effectiveness

July 16, 2013

The U.S. Food and Drug Administration approved marketing of a new test that can determine faster whether steam sterilizers are functioning properly.

Verify Cronos Self Contained Biological Indicator is the first biological indicator test that provides results in two hours. Like other biological indicator tests, the Verify Cronos SCBI consists of a vial containing dried spores from the heat-resistant bacteria Geobacillus stearothermophilus. Prior to the start of a sterilization cycle, the vial is placed inside the sterilization chamber along with the sterilization load. After the sterilization cycle is complete, the spores are placed in a liquid medium ideal for growth of any surviving bacteria. Growth of bacteria indicates that sterilization failed.

The Verify Cronos SCBI test uses a genetically-engineered strain Geobacillus stearothermophilus that produces an enzyme that fluoresces in reaction with the recovery medium if test microorganisms are present after the sterilization process.Genetically engineered Geobacillus stearothermophilus that survive a sterilization cycle will start growing and producing the enzyme within two hours, giving much faster results than the 24 hours normally needed with a natural bacterial strain.

“This is a novel and innovative use of recombinant DNA technology in biological indicator tests,” said Christy Foreman, director of the Office of Device Evaluation in FDA's Center for Devices and Radiological Health. “By providing faster confirmation of sterilization, this innovation may help health care facilities provide their medical staff with a faster turnaround of their sterilized reusable devices.”

The FDA employed the De Novo Classification Process premarket review pathway, a regulatory pathway for low- to moderate-risk medical devices that are not substantially equivalent to an already legally marketed device, to review the data for Verify Cronos SCBI.

To support the De Novo petition, manufacturer Steris Corporation of Mentor, Ohio, tested the performance of the Verify Cronos SCBI, subjecting more than 300 of the indicators to a partial sterilization cycle and then comparing results after two hours and at seven days of incubation in the growth media. Test samples that showed positive growth at two hours also did at seven days.

For more information, visit FDA.