Infections caused by hypervirulent Klebsiella pneumoniae in non-endemic countries: three case reports and review of the literature

Abstract

Objectives: Spontaneous liver abscess caused by a hypervirulent Klebsiella pneumoniae strain was first described several decades ago in Taiwan and has been an emerging clinical entity worldwide ever since. We aimed to describe the clinical and microbiological characteristics of this infection in a non-endemic setting.

Methods: A narrative literature review was conducted in PubMed for European case reports of hypervirulent Klebsiella pneumoniae from 2016 to 2021.

Results: Forty case reports were retrieved. Mean age of the patients was 59 years and 72% were male. Diabetes mellitus was present in 33%. Twenty percent of the patients originated from an endemic region. A liver abscess and bacteremia were observed in, respectively, 83% and 80% of the cases. The most frequent metastatic infections were found in the eye (28%) and the lungs (28%). The sensitivity of molecular capsular antigen detection and the string test was 87% and 92%, respectively. Sixty-three percent of the strains had a wildtype resistance.

Conclusion: Hypervirulent Klebsiella pneumoniae infections in non-endemic countries are most frequently observed in middle-aged males. Clinicians should be vigilant for metastatic infections.

Keywords: Klebsiella pneumoniae; hypervirulent; liver abscess; string test.