Emergence of KPC-producing hypervirulent Klebsiella pneumoniae in a case of fatal recrudescent liver abscess.

A 76-year-old man with pancreatic cancer was readmitted in septic shock due to a recrudescent liver abscess, previously treated with cefepime for four weeks. While only Klebsiella pneumoniae (KP) without acquired resistance was initially isolated from liver abscess cultures, both carbapenem-susceptible KP (CSKP) and carbapenem-resistant KP (CRKP) were identified from liver abscess and blood cultures during this admission. Whole-genome sequencing revealed that CRKP had a chromosome of ST420 containing yersiniabactin genes, blaSHV-75, emrD, fosA, and oqxAB, plus two plasmids: IncX3-type carrying blaKPC-2 and blaSHV-11, and IncHI1B-type carrying aerobactin genes, salmochelin genes, and rmpA. CSKP was ST889 with KL54 capsular type, harboring an IncFIB/IncFII-type plasmid carrying blaCTX-M-15, and multiple additional resistance determinants. The patient died despite 11 days of meropenem, amikacin, and colistin combination therapy. This is the first report of a hypervirulent CRKP of ST420 carrying blaKPC-2.