Highly magnified 12000X, this colorized scanning electron micrograph (SEM) depicted six Gram-negative Legionella pneumophila bacteria. Note that youre able to see a flagella emanating from the lower right organisms. Also note that one bacteria is about to become two, separate entities, as they were finishing the process of cell division. Please see PHIL 11092 through 11152 for additional SEMs of these organisms, specifically PHIL 11109 for a black and white version of this image.
Youll note that a number of these bacteria seem to display an elongated-rod morphology. L. pneumophila are known to most frequently exhibit this configuration when grown in broth, however, they can also elongate when plate-grown cells age, as it was in this case, especially when theyve been refrigerated. The usual L. pneumophila morphology consists of stout, fat bacilli, which is the case for the vast majority of the organisms depicted here.