What is the staining characteristic of Francisella tularensis?

The staining characteristic of Francisella tularensis is best described as faint staining coccobacilli. This particular organism is a small, gram-negative, non-motile coccobacillus, which typically shows weak staining properties when subjected to Gram staining. As a result, it may not take up the crystal violet stain well and can often appear light or faint under a microscope, especially compared to more robustly staining bacteria.

In clinical microbiology, recognizing the characteristics of Francisella tularensis is critical due to its pathogenic nature and the potential for causing tularemia, a serious infectious disease. Understanding its morphology helps in proper identification and subsequent laboratory handling.

The features of other options diverge significantly from Francisella tularensis; for instance, brightly staining cocci would more likely refer to other types of bacteria, while gram-positive bacilli would not accurately represent this organism's gram-negative characteristics. Dark staining rods also do not apply, as Francisella does not present as long, rod-like structures, and typically does not exhibit strong staining. Thus, the faint staining characteristic aligns well with the properties of this specific bacterium.