# Epidemiological and characteristic differences of hypervirulent and classical Klebsiella pneumoniae: a clinical and genomic study in Southern China during the COVID-19 pandemic

## TL;DR

This study examines the differences between hypervirulent and classical Klebsiella pneumoniae in Southern China during the COVID-19 pandemic, finding that hypervirulent strains cause more severe infections and show distinct genomic and clinical features.

## Contribution

The study identifies a rise in hypervirulent K. pneumoniae during the pandemic and reports the emergence of a multidrug-resistant hypervirulent strain in Southern China.

## Key findings

- Hypervirulent Klebsiella pneumoniae (hvKp) was more likely to cause bacteraemia and less likely to cause urinary tract infections compared to classical K. pneumoniae (cKp).
- The K20 capsular serotype was significantly associated with hvKp isolates, and hvKp showed lower multidrug resistance rates compared to cKp.

## Abstract

Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a significant public health threat owing to its ability to cause invasive infections. This study aimed to investigate the clinical characteristics and epidemiological associations of hypervirulent Klebsiella pneumoniae (hvKp) and classical K. pneumoniae (cKp) among patients treated at a tertiary hospital in Zhuhai City, Guangdong Province, China, during the period from January to December 2022, in the context of the ongoing COVID-19 pandemic.

A total of 97 non-duplicated K. pneumoniae isolates and corresponding clinical data were collected. Antimicrobial susceptibility testing, hypermucoviscosity phenotyping, sequence typing, capsular serotyping, and whole-genome sequencing were performed. Hypervirulent strains were identified by the presence of the rmpA, rmpA2, iucA, iroB, peg-344, and peg-589 genes.

Among the 97 isolates, 40 (41.2%) were classified as hvKp. Compared with cKp, hvKp was significantly more likely to cause bacteraemia (P < 0.05) and less likely to cause urinary tract infections (P < 0.05). The K20 capsular serotype was significantly associated with hvKp isolates (P < 0.05). The multidrug resistance rate among hvKp strains (22.5%) was markedly lower than that among cKp strains (56.63%), and extended-spectrum β-lactamase production was more common in cKp strains. Multilocus sequence typing identified 29 sequence types, including 24 novel types. Whole-genome sequencing of a multidrug-resistant hvKp isolate (Kp00198874) revealed an ST11-K64 strain resistant to all tested antibiotics.

The prevalence of hvKp increased during the COVID-19 pandemic in Guangdong, China. The isolates identified in this study represent sporadic infections, and the emergence of ST11-K64 hypervirulent carbapenem-resistant K. pneumoniae (hv-CRKp) highlights the urgent need for continued surveillance and vigilance regarding hvKp-associated bacteraemia.