Impact of Physiological Neutral pH on Morphology of Francisella tularensis – An Electron Microscopic Study

Francisella tularensis is an infectious, gram-negative, coccobacilli bacterium responsible for causing Tularemia. Because F. tularensis is a facultative intracellular bacterium, it must function at physiological pH. However, the bacterium has reduced growth rate at pH 7.4 compared to pH 6.4. This study uses scanning and transmission electron microscopy to demonstrate that physiological neutral pH causes F. tularensis to exhibit morphological changes.