Purpose Characteristic growth patterns in broth may be of use in identifying an unknown bacterium

Principle Growth patterns in broth may be used to distinguish between microbes during identification. These patterns can be characteristic for certain species. Remember, however, that these growth patterns can be influenced by growth conditions such as type of medium used or the temperature of incubation. Additionally, the growth may be disturbed accidentally by shaking or moving the tube.

Additional Information
Terms to described growth patterns of bacterial cultures in broth:

1. uniform turbidity, or diffuse growth
2. flocculent (clumps)
3. sediment, and
4. ring or pellicle growth on surface

 

Left to Right:

Pellicle on surface
Sediment (on the bottom, which is hard to see in this photo)
Uniform Turbidity
Control (unioculated nutrient broth tube without growth)