Klebsiella pneumoniae is a Gram-negative, nonmotile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. Present in the normal flora of the mouth, skin, and intestines, it can cause destructive changes to human lungs if aspirated, specifically to the alveoli, resulting in bloody sputum. In the clinical setting, it is the most significant member of the Klebsiella genus of Enterobacteriacea. Color-enhanced SEM. Image width: 8 micrometers. Magnification: 12,500x if the image is printed 10 cm wide.