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Klebsiella pneumonia

Clinical data

  • The patient was a 27 year old man who died in 1948.

  • Three days before admission he had sudden onset of pleuritic pain on the right side of his chest.

  • He also had a cough with blood-stained sputum.

  • On examination he was flushed and pyrexial. His respiratory rate was increased and there were signs of marked consolidation of both the left and right lungs. 

  • He died the day after admission despite large doses of penicillin.   

Post mortem pathology

  • The specimen is his left lung which has been partially sectioned to show the grey-white areas of pneumonic consolidation. 

    • These areas are not typically lobar (affecting the whole of a lobe) but rather lobular or segmental, that is affecting parts of the lobes. 

    • This is said to be typical of Klebsiella pneumonia.

    • Another feature is that the affected areas appear to be swollen or bulging, which can give rise to the bulging fissure sign on x-ray. See

Left lung which has been partially sectioned to show the grey-white areas of pneumonic consolidation.

  • There is a milky-looking fibrinous exudate on the pleural surface of the lung, seen here on the hilar aspect.

Pleural surface of lung, with milky-looking fibrinous exudate.

  • No pneumonia can be accurately identified without microbiological investigation.
  • A gram negative bacillus with culture characterisitics of Klebsiella pneumoniae was isolated from both lungs.

MacConkey agar

  • K. pneumoniae produces large, mucoid colonies after 24 hours of aerobic incubation. It is a lactose fermenter so on MacConkey agar the colonies are pink, as shown here.  

  • The mucinous quality of Klebsiella would be noted by the pathologist at post mortem; the cut surface of the lungs appears mucinous and the knife used for sectioning would be sticky with mucous.

Some comments

  • Klebsiella pneumoniae and Klebsiella pneumonia are sometimes still called Friedländer’s bacillus and Friedländer’s pneumonia respectively, after the German physician Carl Friedländer, who described them in the 19th century.

  • Klebsiella pneumonia typically occurs in men over 50 years with an underlying  chronic condition such as alcoholism or diabetes.

  • It is an aggressive pneumonia and has a tendency to progress to abscess formation.

  • When this patient fell ill in 1948 antibiotic options were limited. Today the first line antibiotic for community acquired Klebsiella pneumonia is coamoxiclav or a 3rd generation cephalosporin (cefotaxime or ceftriaxone).​​​​​​

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