Klebsiella pneumoniae is a major cause of severe healthcare- and community-associated infections, and both hypervirulent and carbapenem-resistant forms are increasingly reported worldwide. However, the prognostic value of virulence factors remains uncertain. We conducted a systematic review and meta-analysis to evaluate their association with mortality. We searched PubMed, Scopus, and Cochrane Library for studies (2000–2024) reporting virulence factors in K. pneumoniae infections. Meta-analysis compared the prevalence of factors reported in ≥ 5 studies between survivors and non-survivors. Sixteen studies including 2,697 patients (600 deaths, 22.2%) were analyzed. Common virulence factors included hypermucoviscous phenotype, rmpA, iucA, and K1/K2 capsular types. Only sequence type 11 (ST11) was associated with increased mortality in a random-effects meta-analysis (pooled OR 2.43; 95% CI: 1.03–5.77; P = 0.04). Sensitivity analyses confirmed this result’s robustness, even among drug-resistant strains. No significant link between traditional virulence factors and mortality was found. ST11 is a marker associated with increased mortality in K. pneumoniae infections, likely due to its strong link with carbapenem resistance. Antimicrobial resistance appears to influence patient outcomes more than intrinsic virulence factors. Integrating sequence typing and resistance profiles into molecular epidemiology may improve risk assessment and infection control strategies.
Namikawa et al. (Mon,) studied this question.