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Biological indicators are the only process indicators
that directly monitor the lethality of a given
sterilization process. Spores used to monitor a
sterilization process have demonstrated resistance to
the sterilizing agent and are more resistant than the
bioburden found on medical devices.
Bacillus atrophaeus spores are used to monitor
EO Gas and
dry heat, and
Geobacillus stearothermophilus
spores are used to monitor steam
sterilization, hydrogen peroxide gas
plasma, and liquid peracetic acid sterilizers.
Geobacillus stearothermophilus spores are incubated at
55-60°C, and Bacillus atrophaeus spores are incubated
at 35-37°C.
Weekly Testing is minimum:
Steam and low temperature sterilizers (e.g., hydrogen
peroxide gas plasma, peracetic acid) should be
monitored at least weekly with the appropriate
commercial preparation of spores. If a sterilizer is
used frequently (e.g., several loads per day), daily
use of biological indicators allows earlier discovery
of
equipment malfunctions or procedural errors and thus
minimizes the extent of patient surveillance and
product recall needed in the event of a
positive
biological indicator. Each load
should be monitored if it contains implantable
objects. If feasible, implantable items should not be
used until the results of spore tests are known to be
negative. See
also
www.cdc.gov/oralhealth/infectioncontrol/faq/sterilization_monitoring.htm
The
excellent microbicidal activity of ETO sterilizers has
been demonstrated and proven in several studies. ETO
inactivates all microorganisms although bacterial
spores (especially Bacillus atrophaeus) are more
resistant than other microorganisms. For this reason
Bacillus atrophaeus spores is the recommended
biological indicator.
Also, Bacillus atrophaeus spores should be used
to monitor the sterilization process for dry heat
because they are more resistant to dry heat than are
Geobacillus stearothermophilus spores. The primary
lethal process is considered to be oxidation of cell
constituents.
ATS,
Inc. facilitates high quality and stringent laboratory
standards with our
Mail-In Services. We provide a
dual-spore strip inoculated with both spores,
Geobacillus stearothermophilus and Bacillus atrophaeus
spores, allowing users to spore test all sterilizers
used in healthcare facilities. ATS also has a 48-hour
read-out biological indicator for performing
In-Office Testing. |
