SPORICIDAL ACTIVITY OF CHEMICAL AND PHYSICAL TISSUE FIXATION METHODS

Aims - The effects of alcohol based fixation and microwave stimulated alcohol fixation were investigated on spores of Bacillus stearothermop hilus and Bacillus subtilis (var. niger). Methods - Spores were expose d to 10% formalin, or different concentrations of various alcohol cont aining (Kryofix/Spuitfix). Adequate were also set up in conjunction wi th the test solutions. The spores were immersed with and without adjun ctive microwave stimulation in the various solutions tested. Possible surviving spores were recovered in revival broth and after incubation, and Gram staining viable counts were performed. Results - Alcohol bas ed fixatives did not have a sporicidal effect on B stearothermophilus or B subtilis (var. niger) spores, and microwave stimulated alcohol fi xation at 450 W and up to 75 degrees C did not have a sporicidal effec t. Conclusions - When alcohol based fixatives are used for fixation, p recautions should be taken with the material thus treated, as it may c ontain viable spores or other pathogens, which are destroyed after 24 hours of formalin treatment. Of the physicochemical methods tested inv olving microwaving, none was successful in eliminating viable spores f rom the test material.