You've Just Isolated a New Bacterium in Pure Culture, and You

You've just isolated a new bacterium in pure culture, and you culture it on a general purpose medium where its cells have a rod-shape (bacillus) morphology. In addition to culturing it on solid media, you inoculate a slide to grow it as a bio?lm. When you use confocal microscopy to image the bio?lm, you observe that there are several cellular morphologies, ranging from coccus to coccobacillus to long bacillus. The best explanation for this observation is that _______.

A) the bio?lm is no longer a pure culture of the microbe
B) the bio?lm culture was not incubated under the appropriate conditions
C) the microenvironments within a bio?lm promote structural variation
D) the confocal microscope is out of adjustment