Hypervirulent Klebsiella pneumoniae: Characterization, Pathogenesis, and Infectivity

Hypervirulent Klebsiella pneumoniae (HvKp) is an emerging pathogen associated with severe and invasive infections, including pyogenic liver abscesses, septicemia, and pneumonia. Its hypervirulence is linked to enhanced capsular polysaccharide production resulting in hypermucoviscosity, efficient siderophore-mediated iron acquisition, and increased tissue invasiveness. HvKp strains are predominantly associated with capsular serotypes K۱ and K۲. HvKp poses an increasing public health threat due to its rising antimicrobial resistance, which complicates treatment strategies. This review aims to summarize the clinical impact, resistance patterns, and virulence mechanisms of HvKp infections, thereby highlighting their growing significance in clinical microbiology and infectious disease research. HvKp infections are increasingly prevalent, with studies demonstrating that ۱۵–۳۰% of Klebsiella isolates in endemic regions such as China and Taiwan are hypervirulent. These infections are associated with higher mortality rates, ranging from ۸.۱–۱۶.۷% for severe outcomes, including liver abscesses and sepsis. Furthermore, HvKp strains are frequently resistant to multiple antibiotics, with resistance rates to carbapenems ranging from ۱۲–۲۰% and frequent production of extended-spectrum β-lactamases (ESBLs). The hypermucoviscosity phenotype of HvKp contributes to its increased invasiveness, particularly in immunocompromised individuals, although HvKp notably also causes severe disease in immunocompetent hosts, resulting in infections that are particularly severe and difficult to treat. HvKp infections pose a growing global health threat due to their high prevalence, severe clinical outcomes, and increasing antimicrobial resistance. These strains require heightened clinical awareness and surveillance to better manage and prevent transmission, underscoring the need for continued research into their pathogenesis and resistance mechanisms. Ultimately, preventing HvKp infections in both community and hospital settings requires a multifaceted approach, encompassing improved public health practices, management of predisposing conditions such as diabetes mellitus, and stringent infection control measures within healthcare facilities.

کلیدواژه ها:

Klebsiella pneumoniae ، hypervirulent K. pneumoniae (HvKp) ، Hypermucoviscosity ، Virulence factors ، Antimicrobial resistance ، Pathogenesis ، Invasive infections ، Liver abscess