Gram negative rod (GNR) infections cause a significant amount of morbidity and mortality amongst hospitalized patients. Patients with poor underlying medical status are most at risk, especially the immunosuppressed, elderly, and patients with malignancies.

Are rods Gram-negative or positive?

Gram-positive bacilli (rods) subdivide according to their ability to produce spores. Bacillus and Clostridia are spore-forming rods while Listeria and Corynebacterium are not. Spore-forming rods that produce spores can survive in environments for many years.

What Gram-negative rods means?

Gram-negative: Gram-negative bacteria lose the crystal violet stain (and take the color of the red counterstain) in Gram's method of staining. This is characteristic of bacteria that have a cell wall composed of a thin layer of a particular substance (called peptidoglycan).