Carbapenems versus non-carbapenems as definitive treatment for hypervirulent Klebsiella pneumoniae bacteremia in Taiwan

Hypervirulent Klebsiella pneumoniae (hvKp) can cause serious community-acquired pyogenic infections and is prevalent in Asian countries. Unlike classical K. pneumoniae , which is usually multidrug resistant, hvKp is usually antimicrobial-sensitive. However, the optimal definitive treatment for hvKp bacteremia remains unclear, with carbapenems often used due to severe conditions. We aimed to compare clinical outcomes of patients with hvKp bacteremia treated with carbapenems and non-carbapenems in Taiwan. This retrospective study included patients with monomicrobial hvKp bacteremia treated with appropriate definitive therapy at Taipei Veterans General Hospital from January 2015 to December 2017. K. pneumoniae isolates carrying rmpA / rmpA2 genes were defined as hypervirulent strains. A multivariate logistic regression model and propensity score-matched analyses were used to identify independent risk factors for 28-day mortality. A total of 236 patients with hvKp bacteremia were identified, and 52 patients received carbapenems. The non-carbapenem group had a lower 28-day mortality than that in the carbapenem group (10.3% versus 23.1%, P = 0.016). Multivariate analysis showed definitive carbapenem therapy was not associated with 28-day mortality (OR, 1.39; 95% CI, 0.47–4.10; P = 0.549). Among 90 patients with an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥15, definitive therapy with carbapenems was still not associated with 28-day mortality (OR, 2.63; 95% CI, 0.58 to 12.00; P = 0.212). The propensity score-matched analyses yielded similar results. In conclusion, definitive carbapenem therapy for hvKp bacteremia was not associated with a survival benefit compared with non-carbapenem therapy, even in critically ill patients. The study provides valuable insights into antimicrobial stewardship in endemic regions of hvKp.