A fatal case of liver abscess caused by hypervirulent Klebsiella pneumoniae in a diabetic adolescent: A clinical and laboratory study

Abstract

Importance Hypervirulent variants of Klebsiella pneumoniae (hvKp) are capable of causing life‐threatening pyogenic liver abscesses (PLAs), but hvKp caused PLAs was seldom reported in pediatric populations. Hence, there is an urgent need to raise our awareness of this phenomenon in pediatric populations. Objective This study aimed to report the clinical characteristics of hvKp that caused fatal PLA complicated by bacteremia in an adolescent and further identify the microbiological and genomic features of the causative strain. Methods A 14‐year‐old boy with diabetes mellitus was admitted to our hospital with a diagnosis of PLA complicated by bacteremia. A hypermucoviscous hvKp strain, KPN_19‐106, was isolated from the drainage fluid present within the liver abscess cavity and blood. The hypermucoviscosity phenotype of the causative strain was determined by string test. Its virulence was measured using serum resistance assay and Galleria mellonella larvae‐killing assay. Antimicrobial susceptibility was determined by broth microdilution method. Genetic information was obtained by whole‐genome sequencing and bioinformatics analysis. Results KPN_19‐106 belonged to sequence type 380 and serotype K2 and exhibited stronger serum resistance and higher in vivo lethality than the well‐characterized hvKp NTUH‐K2044 strain. Although KPN_19‐106 is susceptible to most antibiotics, no sign of improvement was observed during treatment with such drugs. Whole‐genome sequencing revealed that the isolate had integrated multiple mobile genetic elements related to virulence. Interpretation Antibiotic‐susceptible hvKp can cause fatal PLA complicated by bacteremia in adolescents, with no improvement during antimicrobial therapy. The causative strain in this case had integrated multiple virulence genes and thus exhibited higher virulence both in vitro and in vivo when compared with NTUH‐K2044.

Hypervirulent Klebsiella pneumoniae employs genomic island encoded toxins against bacterial competitors in the gut

“…1B ). Both SL23 and SL380 lineages are associated with KLA, although SL380 is a minor HvKp lineage [ 36 , 37 ]. In all GIE492 + ICEKp10+ isolates, the colibactin and microcin immunity genes clbS and mceB were present ( Supplementary Table 2 ).…”

Hypervirulent Klebsiella pneumoniae in a South African tertiary hospital—Clinical profile, genetic determinants, and virulence in Caenorhabditis elegans

“…Several studies have described the importance of primary pyogenic liver abscess (PLA) or secondary infections (endophthalmitis and meningitis) as invasive infections in community-acquired hvKp patients (Fang et al, 2007 ; Guo et al, 2017 ; Li et al, 2021 ). This includes a study by Liu et al ( 2014 ), who reported that hvKp strains found in the community caused severe infections such as liver abscess and pneumonia.…”

The First Community-acquired Klebsiella variicola Bacterial Meningitis Identified by Metagenomic Next Generation Sequencing

“…4 Digital DDH is the bioinformatics tool based on the principle of DDH with the species boundaries of 70%. 4,5 When the genome of the causative strain ( Klebsiella 20–27) was compared with nine K. variicola , the digital DDH values were 91.6%–97.0% (Fig. 1E).…”