FDA approves sale of biological method to test effectiveness of steam sterilisation

14 July 2013 (Last Updated July 14th, 2013 18:30)

Ohio-based Steris has secured approval from the US Food and Drug Administration (FDA) to market its Verify Cronos self-contained biological indicator (SCBI), a new and faster method of testing the effectiveness of steam sterilisation on reusable medical devices.

surgical equipment

Ohio-based Steris has secured approval from the US Food and Drug Administration (FDA) to market its Verify Cronos self-contained biological indicator (SCBI), a new and faster method of testing the effectiveness of steam sterilisation on reusable medical devices.

Medical devices such as surgical instruments and endoscopes can be reused on patients only when they are thoroughly reprocessed, a multistep process consisting of the devices being cleaned and disinfected or sterilised.

A biological test, the SCBI is used in reprocessing and can provide results in only two hours, unlike the conventional process that takes around a day.

FDA Devices and Radiological Health Center Device Evaluation Office director Christy Foreman said: "By providing faster confirmation of sterilisation, this innovation may help healthcare facilities provide their medical staff with a faster turnaround of their sterilised reusable devices."

Steam sterilisation is a method used for sterilising reusable medical devices, where medical devices are placed in a chamber and then sealed and filled with steam.

In order to destroy micro-organisms present on these devices, certain conditions such as temperature, exposure time and chamber pressure are maintained during the sterilisation process.

Similar to other biological tests, the Verify Cronos SCBI comprises a vial that contains dried spores from the Geobacillus stearothermophilus, a bacteria that is resistant to heat.

Before the sterilisation cycle begins, the vial present inside the chamber is placed along with the sterilisation load.

"By providing faster confirmation of sterilisation, this innovation may help healthcare facilities provide their medical staff with a faster turnaround of their sterilised reusable devices."

After completion of this cycle, the spores are incubated in a liquid that presents an ideal condition for any surviving bacteria to grow and the spore growth is then monitored.

Any growth of bacteria means failure of the load.

The SCBI test uses a genetically engineered strain Geobacillus stearothermophilus, which generate an enzyme that fluoresces in reaction with this liquid medium in case micro-organisms are present following the process of sterilisation.

The genetically-engineered strain that overcomes the sterlisation process will start developing and generating the enzyme within two hours, which enables technicians to identify the results faster than the conventional methods that take 24 hours as they use natural bacterial strain.


Image: Surgical instruments can be reused on patients only when they are thoroughly reprocessed. Photo: courtesy of Spekta.