Community-acquired liver abscess caused by capsular genotype K2-ST375 hypervirulent Klebsiella pneumoniae isolates

Abstract Hypervirulent Klebsiella pneumoniae has been associated with community-acquired liver abscesses in relatively healthy subjects since the 1990s, occasionally accompanied by disseminated disease. While isolates of capsular genotype K1 belonging to sequence type (ST) 23 have been the most prominent causative pathogen of this syndrome, other virulent clones have been implicated sporadically in recent years. A 68-year-old woman with diabetes in Okinawa, Japan suffered from a K. pneumoniae liver abscess, which recurred after a prolonged antibacterial treatment. The clinical course was further complicated with multiple sites of dissemination. Another 45-year-old woman living in Okinawa without underlying conditions was also diagnosed with a community-acquired K. pneumoniae liver abscess, which was cured with antibacterial treatment alone. Both of the causative isolates carried rmpA and aerobactin genes, and were confirmed as capsular genotype K2 and ST375. K. pneumoniae K2-ST375 is a hypervirulent clone of epidemiological significance causing severe community-acquired infections in relatively healthy subjects. More information about clinical characteristics and molecular epidemiology of hypervirulent K. pneumoniae clones other than K1-ST23 should be accumulated.