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Hypervirulent Klebsiella pneumoniae (hvKP) can cause severe invasive infections in healthy and immunocompromised individuals. It is an important clinical pathogen, with the recent identification of highly invasive community-acquired K. pneumoniae that produce purulent liver abscess. Herein, the frequency, clinical characteristics, and molecular epidemiology of K. pneumoniae isolates obtained from January to October 2016 in Wenzhou, China, were examined. In the present study, 33 isolates (68.8%, 33/48) had a positive string test and were identified as hvKP. Both age and sex were associated with a positive string test (p < 0.05). Univariate analysis revealed that liver abscess (odds ratio = 10.154) was a significant risk factor for hvKP. Among the hvKP isolates, K1 was the most common capsular serotype, followed by K2 (p < 0.05). The prevalence of K1 and K2 was significantly higher in hvKP than non-hvKP isolates. The rates of virulence-associated genes, rmpA, iroB, fib, and hib, were significantly higher for hvKP than for non-hvKP (p < 0.05). In this study, kfuB, ybtA, and wcaG were associated with K1 isolates. ST23 was the predominant hvKP type, which belonged to serotype K1. Pulsed-field gel electrophoresis showed that two clusters had >75% similarity and each accounted for >3 isolates. The homology of the 48 clinical isolates was diverse. In conclusion, hvKP isolates had a high frequency of virulence factors and a wide variety of homologs. These results suggest that, because of the toxicity associated with K. pneumoniae, increased clinical understanding of the disease is important to prevent larger, severe outbreaks. [ABSTRACT FROM AUTHOR]

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has posed a great threat to public health. Among 133 nonduplicated CRKP isolates collected between September 2016 and November 2017 in a tertiary hospital in China, 89 (89/133, 66.9%) and 31 (31/133, 23.3%) were positive for blaNDM-5 and blaKPC-2. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) revealed that ST290 represented the majority of NDM-5 producers (67/89, 75.3%) and PFGE cluster E accounted for 50 (50/67, 74.6%) ST290 isolates from the burn ward, suggesting that K. pneumoniae ST290 clone carrying blaNDM-5 resulted in an outbreak in this hospital. Whole genome sequencing of the plasmid carrying blaNDM-5 showed that the resistance gene blaNDM-5 was located in a ∼49 kb multireplicon plasmid with a peculiar insertion of ISKpn19 of the IncX3-type plasmid. To the best of our knowledge, this is the first report of outbreak of K. pneumoniae ST290 clone carrying blaNDM-5. [ABSTRACT FROM AUTHOR]