Table 1:

Features of classical versus hypervirulent Klebsiella pneumoniae infection ^1,2,6–11

Feature	Classical Klebsiella pneumoniae	Hypervirulent Klebsiella pneumonia
Predisposing factors	Older age Immunocompromised	Diabetes First reported in countries or individuals from Asian Pacific Rim, but now emerging globally
Distant spread (apart from hepatic abscess)	None	Multiple sites, including Endophthalmitis Meningitis Pulmonary abscess Splenic abscess Pyelonephritis Epididymitis
Hepatic abscess	Polymicrobial Underlying biliary disease	Monomicrobial No underlying biliary disease Regional thrombophlebitis Radiographic characteristics — single, unilobar, solid, multilocular
Source of infection	Nosocomial	Community
Factors that increase virulence	Not applicable	K1 and K2 capsular serotypes rmpA, rmp2, magA, aerobactin (iuc), salmochelin (iro)
Treatment	Pathogen-directed antimicrobial therapy and abscess drainage	Pathogen-directed antimicrobial therapy and abscess drainage; surgical intervention should be considered if refractory
Antimicrobial resistance	Common	Emerging