Medical devices For sterility examiner training content, you may often hear terms such as positive control, negative control, blank control, etc., control is one of the important methods to obtain reliable results in sterility testing. This article will talk about what controlled trials are.
1.Positive control
The positive control should be selected according to the characteristics of the test product: the test product with no antibacterial effect and anti-Gram positive bacteria is the main test product, and Staphylococcus aureus is the control bacteriaThe test product with Escherichia coli as the control bacteria was mainly anti-gram-negative bacteriaThe test product of anti-anaerobic bacteria, with Clostridium sporangiens as the control bacteria;Antifungal test product, with Candida albicans as the control bacteria. The bacterial solution preparation of the positive control test is the same as the method verification test, the amount of bacteria added is not more than 100cfu, and the amount of test sample is the same as that of the test sample inoculated in each medium of the test product. Positive control tubes should grow well for no more than 5 days.
2.Negative control
When the test sample is tested for sterility, the corresponding solvent, diluent and rinsing solution should be operated in the same way as a negative control. The negative control must not have bacterial growth.
3.Diluent, rinse and preparation method thereof
After the diluent and rinse solution are prepared, they should be sterilized by a sterilization procedure that is qualified for verification.
1）0.1% aqueous solution of sterile peptone take peptone 10g, add 1000ml of water, dissolve at a slight temperature, filter if necessary to clarify, adjust the pH value to 71±0.2. Divide and sterilize.
2）ph7.0 sterile sodium chloride-peptone buffer take potassium phosphate monobasic 356g, anhydrous disodium phosphate 577g, sodium chloride 430g, peptone 10g, add 1000ml of water, dissolve at a slight temperature, filter if necessary to clarify, aliquot, sterilize.
3) According to the characteristics of the test sample, other suitable solutions that have been verified can be selected as dilution and rinsing solution. (e.g. 0.)9% sterile sodium chloride solution).
If necessary, surfactants or neutralizers can be added before or after sterilization of the above dilutions or rinsing solutions.