Experimental models suggest that the combined presence of iucA, iroB, peg-344, rmpA, and rmpA2 reliably distinguishes hypervirulent Klebsiella pneumoniae (hvKp) from classical strains (cKp).We evaluated the clinical relevance of this five-gene definition among adults with K. pneumoniae bacteremia. Methods:We performed a longitudinal study in an hvKp-endemic region in adults with community-acquired K. pneumoniae bacteremia.Isolates were classified as hvKp or cKp according to PCR detection of the concurrent presence of five virulence genes.Clinical characteristics and microbiologic features were compared between groups.Predictors of 28-day mortality were identified using logistic regression analysis. Results:Among 602 patients, 254 had hvKp bacteremia.hvKp infections were associated with higher rates of abscess formation and longer hospital stays.After adjustment for confounders, hvKp was an independent predictor of 28-day mortality.Most hvKp J o u r n a l P r e -p r o o f isolates were susceptible to commonly used antimicrobial agents.The cKp isolates carrying partial combinations of these virulence genes showed clinical and microbiologic characteristics comparable to those lacking all five genes. Conclusions:The five-gene hypervirulence profile delineated a clinically more severe subset of K. pneumoniae bacteremia, characterized by higher morbidity and mortality compared with cKp.These findings support the five-gene definition as a robust marker of hvKp in routine practice.
Chang et al. (Sun,) studied this question.