Bile hemolysis test

Summary

Bile salts, sodium deoxycholate and sodium taurocholate selectively lysed Streptococcus pneumoniae, while other streptococci tolerated them, the mechanism of which is not fully understood. This experiment is from the Mudanjiang Medical College undergraduate 5-year laboratory guide for testing majors

Operation method

Bile hemolysis test

Principle

Bile salts, sodium deoxycholate, and sodium taurocholate selectively lyse Streptococcus pneumoniae, while other streptococci tolerate these actualities by mechanisms that are not fully understood.

Move

Test Methods:

1, plate method: go to 10% sodium deoxycholate solution an inoculation ring, placed on the colony to be examined, 35 ℃ for 30min, observe the results.

2, test tube method: in 0.9ml 18-24h cultivation of the culture solution add 10% sodium deoxycholate solution 0.1ml or bovine bile salts 0.2ml (at the same time with saline as a pair of illuminated tubes), mix well, at 37 ℃ in a water bath in the role of 10-30min.

Results:

1, plate method: the colony is dissolved and disappeared is positive.

2、Test tube method: the culture medium is negative if it is turbid and becomes cool.

Experimental application:

Cultures used in this test should be fresh and live, and sodium deoxycholate should act in a weakly alkaline environment.

This test is mainly used to differentiate Streptococcus pneumoniae from Streptococcus aureus, the former being positive and the latter negative.

Hemolysis test

Alpha hemolysis: or type A hemolysis, in which some of the red blood cells surrounding the colony are destroyed on the blood plate, showing a grass-green ring.

β hemolysis: or B hemolysis, in the blood that class on the colony around the red blood cells completely dissolved, showing a clear transparent hemolysis ring.

Gamma hemolysis: or C-type hemolysis, no red blood cell lysis around the colony on the blood plate, thus no hemolytic ring.

Recognition of hemolysis can be observed on the surface of the blood plate around the colony and puncture by the naked eye, but also can be observed by microscope. In addition to observing peri-colony hemolysis on the isolation plate, it can be confirmed by the following methods.

Experimental material: sheep blood plate

Experimental method: Inoculate the specimen on the sheep blood plate, use the inoculation ring to tie 2-3 places on the blood plate that has been inoculated, so that the bacteria are inoculated deep into the agar layer, and incubate at 35℃ overnight.

Experimental observation: at the place where the inoculation needle passed through, sheep erythrocytes were completely lysed, forming a colorless and transparent zone, which was β-hemolysis. The sheep erythrocytes were partially lysed or not lysed to form a grass-green ring for α hemolysis. No hemolysis ring is γ hemolysis.

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