Hypervirulent Klebsiella pneumoniae defined by a five-gene panel predicts mortality in community-acquired bacteremia

Area of Science:

• Microbiology
• Infectious Diseases
• Genetics

Background:

• Experimental models indicate five specific genes (iucA, iroB, peg-344, rmpA, rmpA2) differentiate hypervirulent Klebsiella pneumoniae (hvKp) from classical strains (cKp).
• The clinical significance of this five-gene definition in human infections remains to be fully elucidated.

Purpose of the Study:

• To assess the clinical relevance of the five-gene molecular definition for identifying hvKp in adult patients with K. pneumoniae bacteremia.
• To compare clinical characteristics, microbiologic features, and mortality rates between hvKp and cKp infections.

Main Methods:

• A longitudinal study was conducted in an hvKp-endemic region.
• Klebsiella pneumoniae isolates from bacteremic patients were classified as hvKp or cKp based on the presence of the five target virulence genes via PCR.
• Clinical data and outcomes, including 28-day mortality, were analyzed using logistic regression.

Main Results:

• Of 602 patients, 254 had hvKp bacteremia, which was associated with higher rates of abscess formation and prolonged hospital stays.
• hvKp was identified as an independent predictor of 28-day mortality after adjusting for confounders.
• Most hvKp isolates remained susceptible to common antimicrobials, while cKp strains with partial gene combinations showed similar characteristics to those lacking all five genes.

Conclusions:

• The five-gene profile effectively defines a clinically severe subset of K. pneumoniae bacteremia with increased morbidity and mortality.
• This molecular definition serves as a reliable marker for hvKp in clinical settings, aiding in patient management and understanding disease severity.