Case 68. Klebsiella pneumonia (76 y-o M)
         
    Autopsied lung with severe pneumonia in a patient with degenerative neuronal disorder    
         
   
Key words : Klebsiella pneumoniae, pneumonia, capsule formation
   
         
   
opportunistic infection
   
     
 
     
Numerous large and long pathogens are dispersed within the edematous alveolar space. The pathogens are not phagocytized by neutrophils (HE, low power).   The long and thick microbes contain centrally located rod-like core (oil immersion, HE). They were negative with PAS, Grocott and Gram stains.
     
 
     
Chains of rods and covering capsule can be distinguished by methylene blue stain on a paraffin section (oil immersion).   The centrally situated rods are recognizable by Warthin-Starry's silver stain (oil immersion).
     
 
     
The centrally situated rods are also recognizable by immunostaining for heat shock protein-60 (HSP60). Most bacteria commonly express HSP60 (immunostaining after heating treatment).   Gram stain for the sputum
Chains of rods and covering capsule can be distinguished by Gram stain (oil immersion). The knowledge of morphological variations of the microbes is important for diagnostic pathologists.
     
   
     
Methylene blue stain for cultured Klebsiella pneumoniae
Capsule formation is evident in the cultured microbes (oil immersion). Representative capsule forming bacteria include K. pneumoniae, N. meningitidis, H. influenzae, and P. aeruginosa.