What type of bacteria is Francisella tularensis?

Francisella tularensis is classified as a Gram-negative bacterium. This classification is based on the characteristics of its cell wall structure, which is thinner than that of Gram-positive bacteria and comprises an outer membrane containing lipopolysaccharides. In the Gram staining procedure, F. tularensis does not retain the crystal violet dye and instead takes up the counterstain, resulting in a pink appearance under the microscope.

Furthermore, this bacterium is of significant concern in public health as it causes tularemia, a highly infectious disease. Understanding its Gram-negative status is vital for microbiological studies and practical applications in clinical settings, as Gram-negative bacteria typically show a higher resistance to antibiotics due to their cell wall configuration.

The other classifications do not accurately represent the characteristics of Francisella tularensis: it does not exhibit properties of being facultative anaerobic, nor does it form spores, which are features associated with other bacterial species.