The best dream book on the internet.
Find your dream: A-Z list:

Bacteria

    The appearance of bacteria in a dream concerns material matters, it is a warning against negative thoughts and emotions. Depending on the context of the dream, bacteria can herald success or failure.
    look at them under the microscope - your actions or projects will be successful
    fight - sleep is a call to be more diligent
    to have - you suppress negative emotions
    to be afraid of them - you tend to complicate matters unnecessarily.

More dream interpretation: