This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research article
Min Li
Shanghai Jiao Tong University School of Medicine
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0578-7538
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: Although carbapenem-resistant Klebsiella pneumoniae (CRKP) and hypermucoviscous K. pneumoniae (HMKP) were largely non-overlapping, the recent emergence of CR-HMKP has raised great alarm in the world. We compared the molecular characteristics of CRKP, HMKP and CR-HMKP isolates.
Results: 220 cases of K. pneumoniae isolates was collected and identified between Jan 2015 and Dec 2016 from Renji Hospital. Carbapenem resistance test and string test were performed to screen CRKP, HMKP and CR-HMKP isolates. All the CRKP, HMKP and CR-HMKP isolates were investigated for capsular genotyping, virulence genes and resistance genes by PCR and DNA sequencing. Multilocus sequence typing (MLST) was used to characterize isolates sequence types (STs). Serum killing assay and mouse lethality assay were respectively performed to confirm the virulence of the isolates in vitro and in vivo. Of 220 K. pneumoniae，71 HMKP, 84 CRKP and 8 CR-HMKP were identified. Resistance rate to carbapenems was significantly higher in CRKP than HMKP and CR-HMKP. For MLST and serotyping, ST23 (26.8%)，K1 (33.8%) and K2 (23.9%) serotypes were the most common in HMKP isolates while ST11 (84.5%, 100%) and K-nontypable (91.6%, 100%) were the predominant types in CRKP and CR-HMKP isolates. The existence of virulence genes rmpA, magA and iutA was significantly higher in HMKP while the prevalence of resistance gene blaKPC-2 was higher in CRKP and CR-HMKP. Virulence test in vivo and in vitro both showed the lower virulence of CRKP and CR-HMKP compared to HMKP.
Conclusions: In spite of low virulence, the emergence of CR-HMKP indicates a confluence of hypermucoviscous phenotype and carbapenem resistance. Furthermore, the similar molecular characteristics between CRKP and CR-HMKP suggested that CR-HMKP might evolve from CRKP.
Keywords
Carbapenem-resistant, Hypermucoviscous, Klebsiella pneumoniae, CRKP, HMKP, CR-HMKP
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This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research article
Min Li
Shanghai Jiao Tong University School of Medicine
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0578-7538
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 13 Mar, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: Although carbapenem-resistant Klebsiella pneumoniae (CRKP) and hypermucoviscous K. pneumoniae (HMKP) were largely non-overlapping, the recent emergence of CR-HMKP has raised great alarm in the world. We compared the molecular characteristics of CRKP, HMKP and CR-HMKP isolates.
Results: 220 cases of K. pneumoniae isolates was collected and identified between Jan 2015 and Dec 2016 from Renji Hospital. Carbapenem resistance test and string test were performed to screen CRKP, HMKP and CR-HMKP isolates. All the CRKP, HMKP and CR-HMKP isolates were investigated for capsular genotyping, virulence genes and resistance genes by PCR and DNA sequencing. Multilocus sequence typing (MLST) was used to characterize isolates sequence types (STs). Serum killing assay and mouse lethality assay were respectively performed to confirm the virulence of the isolates in vitro and in vivo. Of 220 K. pneumoniae，71 HMKP, 84 CRKP and 8 CR-HMKP were identified. Resistance rate to carbapenems was significantly higher in CRKP than HMKP and CR-HMKP. For MLST and serotyping, ST23 (26.8%)，K1 (33.8%) and K2 (23.9%) serotypes were the most common in HMKP isolates while ST11 (84.5%, 100%) and K-nontypable (91.6%, 100%) were the predominant types in CRKP and CR-HMKP isolates. The existence of virulence genes rmpA, magA and iutA was significantly higher in HMKP while the prevalence of resistance gene blaKPC-2 was higher in CRKP and CR-HMKP. Virulence test in vivo and in vitro both showed the lower virulence of CRKP and CR-HMKP compared to HMKP.
Conclusions: In spite of low virulence, the emergence of CR-HMKP indicates a confluence of hypermucoviscous phenotype and carbapenem resistance. Furthermore, the similar molecular characteristics between CRKP and CR-HMKP suggested that CR-HMKP might evolve from CRKP.
Figure 1
Figure 2
Figure 3
This is a list of supplementary files associated with this preprint. Click to download.
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