Wenqing Wang,1,2,* Chuchu Ye,2,3,* Bing Zhao,1 Yingjie Zheng,4 Ge Zhang,5 Jinghua Su,1 Hong Huang,1 Lipeng Hao,1,2 Mingliang Chen6 

1Department of Microbiology, Pudong New Area Center for Disease Control and Prevention, Shanghai, People’s Republic of China; 2Fudan University Pudong Institute of Preventive Medicine, Shanghai, People’s Republic of China; 3Department of Infectious Disease Control and Prevention, Pudong New Area Center for Disease Control and Prevention, Shanghai, People’s Republic of China; 4Department of Epidemiology/Key Laboratory for Health Technology Assessment, National Commission of Health and Family Planning/Key Laboratory of Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai, People’s Republic of China; 5School of Public Health, Dali University, Yunnan, People’s Republic of China; 6Research and Translational Laboratory of Acute Injury and Secondary Infection, and Department of Laboratory Medicine, Minhang Hospital, Fudan University, Shanghai, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Mingliang Chen; Lipeng Hao, Email cmlbright@126.com; hlpmail@126.com

Background: The occurrence and dissemination of hypermucoviscous and hypervirulent Klebsiella pneumoniae (hm-hvKp) isolates in clinical settings are a critical public health problem in the world. However, the data on these isolates in community populations are limited. This study aims to understand the prevalence and molecular characteristics of hm-hvKp isolates in community patients in Shanghai, China.
Methods: In 2018, an active surveillance system focused on hm-hvKp in community diarrhoeal cases was implemented in Pudong New Area, Shanghai, China, involving 12 sentinel hospitals. The antimicrobial susceptibility of hm-hvKp isolates from fecal samples was tested, and whole-genome sequencing (WGS) was performed to predict the serotypes and sequence types and to identify antimicrobial resistance determinants, virulence determinants, and phylogenetic clusters.
Results: The overall prevalence of hm K. pneumoniae isolates was 2.48% (31/1252), with the proportions of 1.76% (22/1252) for hm-hvKp and 0.72% (9/1252) for hm not hv K. pneumoniae. The prevalence of hm-hvKp isolates among different age groups and different months was statistically significant. All the 22 hm-hvKp isolates were susceptible to 20 antimicrobial agents and only carried blaSHV gene, and KL1 and KL2 accounted for eight (36.36%) cases and seven (31.82%) cases, respectively. The eight ST23/KL1 isolates belonged to the predominant CG23-I clade, which typically possessed the virulence determinants profile of rmpA/rmpA2-iro-iuc-ybt-irp-clb. The five ST86/KL2 isolates were assigned to the global clusters ST86/KL2-1 (n=2), ST86/KL2-2 (n=2), ST86/KL2-3 (n=1), all lack of the clb gene. Shanghai ST23/KL1 and ST86/KL2 isolates were closely related to the global isolates from liver abscesses, blood, and urine.
Conclusion: Hm-hvKp is carried by the community population of Shanghai, with ST23/KL1 and ST86/KL2 isolates predominant. Hm-hvKp isolates of different continents, different sources, and different virulence levels were closely related. Ongoing surveillance of hm-hvKp isolates in the community population is warranted.

Keywords: hypermucoviscous, hypervirulent, Klebsiella pneumoniae, drug resistance determinants, virulence determinants, whole-genome sequencing