Clinical Characteristics, Complications, and Outcomes of Hypervirulent Klebsiella pneumoniae Liver Abscess: A Systematic Review of 53 Cases.

Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging cause of pyogenic liver abscess (PLA), characterized by virulence genes, such as rmpA and rmpA2, as well as capsular types K1/K2 that enhance mucoviscosity and invasiveness. Although regionally predominant in East Asia, cases are increasingly reported worldwide. We reviewed case reports and case series published between 2000 and 2025 describing hvKp-related PLA with individual-level data. Clinical, microbiological, and outcome variables were summarized descriptively due to heterogeneity across reports. Fifty-three patients from 34 studies were included, mainly from Japan, South Korea, and China. The mean age was 66.2 years, and 81% were male. Diabetes mellitus was the most frequent comorbidity (57%). Reported virulence factors included rmpA (43%), magA (25%), and K1 (43%) or K2 (19%) serotypes. Metastatic infection occurred in 36% of cases, most commonly endophthalmitis (36%), followed by pulmonary (19%) and central nervous system involvement (15%). No carbapenemase-producing strains were identified; most isolates remained broadly susceptible. Third-generation cephalosporins (53%) and carbapenems (26%) were the main therapies, often combined with percutaneous drainage (45%). Overall mortality was 6%, and 23% experienced permanent vision loss. hvKp liver abscess generally carries a low mortality but a high risk of disabling metastatic complications. Early ophthalmologic evaluation and vigilant surveillance for dissemination are essential, and recognition of virulence markers distinguishes hvKp PLA from multidrug-resistant Klebsiella pneumoniae infections.