Define the Agar Shake Tube Method

The agar shake tube method is useful for isolation of anaerobic microorganisms. What are anaerobic microorganisms? You may recall the theory course that anaerobic microorganisms are those which grow best in the absence of free oxygen. Few examples of anaerobic microorganisms include: Clostridium perfringens, C. botulinum, Bacillus cereus, Campylobacter, E. coli etc.

In preparing pure culture using agar shake tube method, the dilutions of the mixed microbial suspension are made in tubes of molten agar. The colonies formed are embedded in the agar medium. The isolated colony from the highest dilution is used to make further dilution in a new set of molten agar, resulting in a pure culture.