Klebsiella pneumoniae

It is usually seen as a nosocomial pathogen showing wide prevalence of antibiotic resistance such as ESBLs (extended spectrum beta lactamases).

Human Pathology

It is mainly associated with respiratory infections such as pneumonia, lung abscess, UTIs, wound infections, sepsis and meningitis. Typically seen in a hospital setting or in immunodeficient individuals such as in old age, chronic diabetics, chronic alcoholics etc. In pneumonia very characteristic “currant jelly” sputum is produced. Can you think why it is so? Hint : has to do with a colony characteristic.

Interestingly there are two other species found infrequently. Just to know, Klebsiella ozaenae causes atrophic rhinitis while Klebsiella rhinoscleromatis causes granulomas in the nose and upper respiratory tract.

Laboratory diagnosis of Klebsiella infections

Gram stain and culture of the samples is done. Capsule will show up as a halo around the Gram negative bacillus on a Gram stain. Colonies will be mucoid and lactose fermenting on Mac Conkey’s agar and EMB. It is urease positive.