Klebsiella pneumoniae is usually found in the nasopharynx, intestines, feces, and can also originate from the air, water, and soil. Klebsiella pneumoniae are parthenogenetic anaerobes that colonize the gastrointestinal tract and nasopharynx of humans and other primates. Klebsiella pneumoniae is an intestinal bacterium that is also found in the gut of a small percentage of healthy people. Klebsiella pneumoniae is an opportunistic pathogen that is not highly contagious, but can form aerosols for transmission. Patient morbidity is the result of the interaction between the invasion of Klebsiella pneumoniae, risk factors and the resistance of the host. When the bacterial concentration is highly infectious or the person has poor resistance, Klebsiella pneumoniae multiplies and toxins are produced, causing lung congestion, edema, exudation, and even hemorrhage and necrosis. In most cases, the inflammatory response is manageable, but when the inflammatory response is severe, an inflammatory outbreak may occur, requiring prompt medical attention.