Clinical and genomic profiling of <i>Klebsiella pneumoniae</i> in liver abscesses

Klebsiella pneumoniae (K. pneumoniae) is an opportunistic Gram-negative pathogen responsible for a variety of infections, including liver abscesses (LA). These are associated with hypervirulent K. pneumoniae (hvKp). This study aimed to characterize the clinical and molecular features of K. pneumoniae from patients with LA at a German tertiary care hospital over a 2-y period (2022–2023). Among 111 recorded LA, K. pneumoniae was detected in 27% (n = 30) of cases. Of these, 12 patients had monomicrobial LA. Clinical metadata, including patient demographics, underlying diseases, and microbiological findings, were analyzed and correlated with genomic data to explore associations between genetic traits and clinical presentations. We identified seven cases of hypervirulent K. pneumoniae liver abscesses (hvKpLA) and five cases of non-hypervirulent K. pneumoniae liver abscesses (KpLA). The study found that hvKp was most commonly associated with specific sequence types (ST23-KL1, ST86-KL2) and hypervirulence-associated plasmids. Phylogenetic analysis revealed high genetic diversity, with no evidence of nosocomial transmission. Notably, diabetes mellitus (DM) was observed for five cases and may represent a risk factor for severe K. pneumoniae infections. In conclusion, monomicrobial K. pneumoniae LA infections were caused by hypervirulent strains in 58% of cases. Further, an hvKp case prevalence of 6.3% was estimated among all recorded liver abscesses. These findings contribute to a better understanding of the molecular epidemiology of hvKp and emphasize the importance of integrating clinical and genomic data for more accurate risk stratification and surveillance.