Clinical characteristics and manifestations in patients with hypermucoviscous Klebsiella pneumoniae bacteremia from extra-hepatobiliary tract infection

Purpose: Hypermucoviscous strains of Klebsiella pneumoniae (KP) are associated with invasive liver abscess syndrome. However, little is known about the characteristics of this phenotype in non-hepatobiliary infections. In this study, we investigated the clinical characteristics of patients with hypermucoviscous Kp (hmvKp) bacteremia from non-hepatobiliary tract infection. Methods: This retrospective cohort study was implemented at Samsung Changwon Hospital. From March 2018 to December 2019, adult patients (≥ 18 years) with KP bacteremia of the extra-hepatobiliary system were enrolled. Hypermucoviscosity was defined by the string test. Clinical characteristics and 30-day all-cause mortality between patients with hmvKp and non-hmvKp bacteremia were compared. Results: Among 179 cases of non-hepatobiliary KP bacteremia, 67 (37.4%) and 112 (62.6%) isolates were classified as hmvKp and non-hmvKp, respectively. In the hmvKp group, metastatic infection (9.0 vs. 1.8%, P = 0.054) and purulent or necrotizing infection (31.3 vs. 9.8%, P < 0.001) were more frequently observed. Additionally, non-hmvKp had more frequent resistance to cefotaxime (11.9 vs. 38.4%, P < 0.001). Thirty-day all-cause mortality was similar in the hmvKp (41.8%) and non-hmvKp (39.3%) groups (P = 0.643). In multivariable analysis, septic shock (adjusted hazard ratio [aHR] = 3.05, 95% confidence interval [CI]: 1.22–7.63) and Pitt bacteremia score (aHR = 1.23 per 1 point, 95% CI 1.14–1.33) were associated with increased mortality in patients with Kp bacteremia, while urinary-tract infection (aHR = 0.38, 95% CI 0.18–0.76) was associated with decreased mortality. Conclusion: hmvKp was associated with less frequent drug resistance and metastatic-purulent presentation in non-hepatobiliary infection like in hepatobiliary infection. However, hmvKp was not associated with clinical outcomes.