Abstract
The rise of a new hypervirulent variant of Klebsiella pneumoniae (hvKp) was recently reported, mainly linked to the ST23 lineage. The hvKp variants can cause severe infections, including hepatic abscesses, bacteremia, and meningitis, with a particularly disconcerting propensity to cause community-acquired, life-threatening infection among young and otherwise healthy individuals. The present study aimed to report the clinical characteristics of a hypermucoviscous K. pneumoniae strain isolated in Italy and sustaining recurrent meningitis in a patient of Peruvian origin. A further objective was to retrospectively investigate, by means of whole-genome sequencing (WGS) analysis, the genomic features of such an isolate. The hypermucoviscosity phenotype of the strain (sk205y205t) was determined using the string test. Genomic information was obtained by WGS (Illumina) and bioinformatic analysis. Strain sk205y205t was susceptible to most antibiotics, despite the presence of some resistance genes, including blaSHV-11, blaSHV-67, fosA, and acrR. The isolate belonged to ST65 and serotype K2, and exhibited several virulence factors related to the hvKp variant. Among these, were the siderophore genes entB, irp2, iroN, iroB, and iucA; the capsule-regulating genes rmpA and rmpA2; and the type 1 and 3 fimbriae fimH27 and mrkD, respectively. A further operon, encoding the genotoxin colibactin (clbA-Q), was also identified. The virulence plasmids pK2044, pRJA166b, and pNDM. MAR were also detected. Phylogenetic investigation showed that this Italian strain is highly similar to a Chinese isolate, suggesting a hidden circulation of this hvKp ST65 K2 lineage.
Highlights
The rise of a new hypervirulent variant of Klebsiella pneumoniae was recently reported
The present study aimed to report the clinical characteristics of a hypermucoviscous K. pneumoniae strain causing meningitis, and to retrospectively investigate, by means of whole-genome sequencing (WGS) analysis, the genomic features of such an isolate
K. pneumoniae was isolated from both blood samples and cerebrospinal fluid (CSF) by culture in agar plates
Summary
The rise of a new hypervirulent variant of Klebsiella pneumoniae (hvKp) was recently reported. The hvKp variant was first described in Taiwan, causing invasive pyogenic liver abscess [1,2], but can be responsible for other invasive diseases, including abscesses at other body sites (e.g., eyes, brain, prostate, and kidney), necrotizing fasciitis, severe pneumonia with bacteremia, and meningitis [3]. HvKp infection appears to often occur in diabetic patients, a disconcerting problem is its ability to cause community-acquired, life-threatening infection among young and healthy individuals [4]. HvKp variants are susceptible to most antibiotics, except inherently resistant ampicillin, while several virulence factors have been identified [6]. Several sequence types (ST) have shown to be associated with hvKp, with ST23 being the most represented, related to the K1 serotype, followed by ST83 and ST65, associated with the K2 serotype [3]
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