[Liver abscess caused by hypermucoviscous Klebsiella pneumoniae]

Hypervirulent Klebsiella pneumoniae (hvKP) represents an emerging highly virulent subtype, associated with cryptogenic liver abscesses and severe metastatic infections. First described in Asia in the 1980s, its global spread has been progressive, with a recent increase in reported cases in Argentina. It is characterized by a hypermucoviscous phenotype demonstrated by the "string test," capsular serotypes K1 and K2, and specific genetic determinants that confer resistance to phagocytosis and complement-mediated killing. We report the case of a 34-year-old man without major comorbidities who presented with persistent fever, nausea, and asthenia. Laboratory tests revealed markedly elevated acute-phase reactants and a hepatocellular pattern of liver injury. Computed tomography demonstrated a multiloculated liver abscess in segment VII. After an initial failed attempt at percutaneous drainage, effective drainage was achieved one week later, with isolation of hypermucoviscous K. pneumoniae. The patient received prolonged antibiotic therapy with a favorable clinical course and complete resolution of the abscess. This case reinforces the presence of hvKP syndrome in our setting, even among patients without classical risk factors such as diabetes, and highlights the importance of maintaining a high index of suspicion in liver abscesses without an evident biliary source, as well as the need for epidemiological surveillance in light of the potential convergence of hypervirulence and antimicrobial resistance.