Question

-A surgical technologist working in the Central Sterile Processing Department is asked to run the steam sterilizer (autoclave) with a biological monitor for the first load of the day without any instrument trays or items. 1. Which type of bacteria would be used to test the autoclave? 2. Which characteristic of the species used determines whether sterility was achieved when autoclaved? 3. What must be done with the bacterial sample after it is processed in the sterilizer? 4. Do the bacteria used for biological testing of sterilizers pose any threat to humans? 5. If the biological indicator showed positive growth following the process in question 3, what would have to be done?

Answer 1

Central sterile supply department is the unit within the hospital responsible for supplying all the wards and units in the hospital with sterile articles and equipments especially in the Operation theatre. There are various types of sterilization methods and Autoclaving is one of the most effective methods. To check the sterility of autoclave machine, there are mainly two methods ie. Chemical methods and biological method.

Biological indicators mainly consist of rod shaped gram positive bacteria called Geobacillus Stearothermophillus, which is a thermophilic bacterium and grows best at 55C.

1. Rod shaped gram positive bacteria called Geobacillus Stearothermophillus bacteria is used to check the autoclave machine.

2. The characteristic Quality that helps to check the sterility of autoclave machine is the thermophilia. This organism grows in a temperature of 30-75 C.

3. The bacterial sample comes in a vial. This is being put inside the autoclave machine to be tested. After the machine goes off, wait for 10 mins to allow the vial to cool. After the vial is cool the organism should be put in the container provided by the manufacturer and incubate it at 55 C and time as suggested by the manufacturer. Is the colour does not change, it means organism are non reactive and dead. But if the colour becomes cloudy, it means the organism are alive and the autoclave machine has failed in it's test.

4. The organism Geobacillus Stearothermophillus isnt harmful for human beings.

5. Incase of biological test coming positive, the results should be counter checked by monitoring precious physical and chemical indicators. If the physical and chemical indicators are are negative for bacterial growth, then the fault might not be of the machine but the operator who has worked with the Autoclaving. Reviewing of loading , packing, cleaning and spore testing should be tested with all technicians. Overloading, power supply failure etc. Can lead to bacterial growth. After correcting all these, the biological test should should be conducted immediately. If machine is still showing positive results, shut down that machine.