Epidemiological and Molecular Characteristics of Hypermucoviscous and Hypervirulent Klebsiella pneumoniae Isolates in Community Patients in Shanghai, China

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 limited. This study aims to understand the prevalence and molecular characteristics of hm-hvKp isolates in community patients 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 hmhvKp 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 bla SHV gene, and KL1 and KL2 accounted for eight (36.36%) cases and seven (31.82%) cases, respectively. The eight ST23/KL1 isolates belonged 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.