Case 54. 
Spheroplasts and filamentous change of Klebsiella pneumoniae in bile (50 y-o F)
    Percutaneous drainage of gallbladder bile in case of acute cholecystitis after antibiotics treatment    
Key words : 
Klebsiella pneumoniae, spheroplast, filamentous bacteria, biofilm infection    
Gram-negative rods often change their morphology after antibiotics treatment. In this case, K. pneumoniae shows marked elongation and spheroid change (Papanicolaou, low power).   The morphological alteration of bacteria, somewhat resembling fungi, is due to the effect of β-lactam antibiotics onto the penicillin-binding proteins (Papanicolaou, high power).
The filaments and spheroplasts are Gram-negative. Culture of the bile was positive for K. pneumoniae (Gram).   Reference case 54A
Gallbladder adenocarcinoma with infection of long bacilli (Giemsa). Giemsa staining clearly demonstrates bacteria in the cytology specimen. Diagnostic comments are necessary not only for malignancy but also for bacterial infection.
Reference case 54B
Gallbladder adenocarcinoma with infection of rods embedded in mucoid stroma (biofilm) (Papanicolaou, low power). Biofilm infection generally represents a state of resistance to antibiotics therapy.
  Reference case 54B
Biofilm infection showing rods clustered in the mucoid material (Papanicolaou, high power). The most likely bacterial species in this case is Pseudomonas aeruginosa.