不同浓度白色念珠菌连续培养对比观察.

Objective To investigate the suitable observation concentration in the count of Candida albicans plate dilu-tion method by comparatively observing the growth situation in different concentrations of Candida albicans in LB nutrient agar culture plate. Methods The Candida albicans stock solution was diluted to about 1.5 ×109cfu/m L with No. A. Then 7 sterile tubes with 20 m L were taken, each tube was added with 9 m L sterile normal saline with No. B-H. One m L of bacterial solution was absorbed from the tube A to the tube B, after mixing, 1 m L of bacterial solution was absorbed again to the tube C, so did successive multiple proportion dilution to the tube H. 100 μL of different concentrations of Candida albicans suspension was absorbed by pipette to the one-off agar plate with corresponding number, which was evenly coated with the inoculating loop and cultured at 37 ℃incubator. Results After 48 h culture, Candida albicans with the order of magnitude 104 had smaller thallus with smaller volume than the order of magnitude 102, 103, while 105 was even more denser and smaller volume than 104, which was needle-shaped, its actual morphology was not easier to be observed by naked eye. When the orders of magnitude of Candida albicans was 102, 103, the fungal counting was 20-300 and could be counted, whereas the concentration orders of magnitude reached more than 104, which could not be counted. After 24, 48, 72 h culture, the agar culture plate was taken out for observing. The colony could be visually observed after 24 h culture, but the actual form was not obvious. After culturing for 48 h, the volume was large than that after culturing for 24 h culture, rough morphology could be seen, milky white round or oval, smooth surface and moist, shiny, diameter of1.0-2.0 mm. The volume after 72 h culture was slightly larger than that after 48 h culture, but the bacterial color was yellow. Conclusion The bacterial solution concentration of 1.5×102cfu/m L can be used as the suitable counting concentration of plate dilution method, culturing for 48 h is the best time to observe the colony morphology. [ABSTRACT FROM AUTHOR]