ClorDiSys
uses Biological Indicators (BIs) to verify the efficacy of our
decontamination cycles. Also known as spore strips, the BIs we use consist of
over a million (1 x 106) Geobacillus stearothermophilus spores
inoculated on a paper substrate and wrapped in Tyvek. The chlorine dioxide gas molecule is
small enough to permeate the Tyvek and kill the spores inside. To
challenge the decontamination/sterilization cycle, BIs are placed in hard to
reach areas throughout the space being decontaminated. Once the decontamination
has been completed, the BIs are dropped into growth media using aseptic
technique. If the biological indicator does not produce growth within the media
tube after the incubation period (we have validated a 36 hour incubation time
with the BI manufacturer Crosstex), the process is deemed to be successful.
Below
are some of the more challenging locations where Biological Indicators have
been placed during chlorine dioxide gas decontaminations. All of these
locations’ BIs exhibited 6-log sterilization level kill using our standard
cycle.
Inside Packed Isolators
(Over 30 BIs were placed inside)
In Stacks of Filtered Cage Lids
(Blue tape on right corresponds to BIs shown in left image)
Underneath Dust
(Comparable to that of HEPA filters)
In HEPA Filters
(BI between the filter's pleats)
In Packed Storage Rooms
(BI placed at the bottom of the closest trash can)
