Under a high magnification of 10000X, this colorized scanning electron micrograph (SEM) depicted a grouping of Gram-negative Legionella pneumophila bacteria. Note that you’re able to see a number of the flagella emanating from these organisms.
You’ll 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 they’ve 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.
These bacteria originated on a 1 week-old culture plate (+/- 1 day), which had incubated a single colony, at 37°C upon a buffered charcoal yeast extract (BCYE) medium with no antibiotics.
Source: CDC/ Bette Jensen, Janice Haney Carr
