Prevalence of Carbapenem-Resistant Hypervirulent Klebsiella pneumoniae and Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae in China Determined via Mouse Lethality Tests
Dakang Hu, Wenjie Chen, Qi Zhang, Meng Li, Zehua Yang, Yong Wang, Yunkun Huang, Gang Li, Dongxing Tian, Pan Fu, Weiwen Wang, Ping Ren, Qing Mu, Lianhua Yu, Xiaofei Jiang
Abstract
Objective To investigate the epidemiology of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-HvKP) and hypervirulent carbapenem-resistant Klebsiella pneumoniae (Hv-CRKP). Methods Totally 436 K. pneumoniae strains were collected from 7 hospitals in mainland China between 2017.01 and 2018.02. Sequence types, serotypes, antimicrobial-resistance and virulence genes were analyzed. Additionally, string test, capsule stain, Periodic Acid Schiff stain, fitness analysis, quantitative real-time PCR and mouse lethality test were also performed. Molecular combinations were used to screen putative bla KPC (+)-HvKP and Hv- bla KPC (+)-KP, followed by the confirmation of mouse lethality test. Results Diverse detection rates were found for the virulence genes, ranging from c-rmpA (0.0%) to entB (100.0%). According to the molecular criteria, 127, 186, 9 and 26 strains were putatively denoted as HvKP, bla KPC (+)-KP, bla KPC (+)-HvKP and Hv- bla KPC (+)-KP. Mouse lethality test confirmed 2 bla KPC (+)-HvKP strains (JS184 and TZ20) and no Hv- bla KPC (+)-KP. JS184 showed K2 serotype, thin capsule, positive exopolysaccharid and string test. TZ20 presented K20 serotype, thin capsule, negative exopolysaccharide and string test. Compared with the positive control NTUH-K2044, equal galF expression and growth curves were confirmed for JS184 and TZ20. Conclusions Molecular determination of CR-HvKP and Hv-CRKP brings remarkable bias compared with mouse lethality test. The exact prevalence of CR-HvKP is less than 1.0%, which of Hv-CRKP is much lower.