Pyogenic Liver Abscess And Endogenous Endophthalmitis Due To K64-St1764 Hypervirulent Klebsiella Pneumoniae: A Case Report

Rationale: Klebsiella pneumoniae (K. pneumoniae, KP) are divided into two types: classic K. pneumoniae (cKP) and hypervirulent K. pneumoniae (hvKP). hvKP causes liver abscess and metastatic infection. Here, we report one case with pyogenic liver abscess (PLA) and endogenous endophthalmitis (EE) due to a relatively rarely reported serotype of K. pneumoniae in China.Patient Concerns: An 80-year old man presented with nausea, vomiting, and epigastric discomfort for 2 weeks.Diagnoses: PLA was identified by CT scan and abdominal ultrasound. Urgent ophthalmologic consultation was performed. B-scan ocular ultrasound was done and he was diagnosed as EE.Interventions: Antibiotic treatment, intravitreal injection of eyes and eye drops were given. Percutaneous needle aspiration, evisceration, and drainage of the right eye were performed.Outcomes: Cultures of the blood, the aspirated pus from the liver abscess, and the contents of the eyeball all yielded K. pneumoniae with a positive string test. The capsular serotype was K64. According to the existence of multiple virulence genes and the severe invasive clinical manifestation, this strain is regarded as a hvKp strain. Multilocus sequence typing (MLST) revealed the sequence type (ST) of this strain was K64-ST1764. Antimicrobial resistance genes, bla(NDM-1) and bla(KPC-2), were not detected in the genome. The patient lost his eyesight but his symptoms subsided. During 15 months follow-up, the result was satisfactory.Lessons: Here, we report one case with PLA due to a relatively rarely reported serotype of K. pneumoniae in China. This K64 K. pneumoniae strain is confirmed as hvKp by multiple methods. It is noteworthy that the sequence type is K64-ST1764 instead of the commonest ST11. Moreover, this strain is not considered a K. pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) or a carbapenem-resistant K. pneumoniae (CRKP) as it is usually. Further follow-up and research are required to investigate this strain.