|Year : 2017 | Volume
| Issue : 1 | Page : 145-146
Emergence of ST39 and ST656 extensively drug-resistant Klebsiella pneumoniae isolates in Wenzhou, China
Haiyang Liu1, Jonathan Wilksch2, Bin Li1, Jia Du1, Jianming Cao3, Xiaoxiao Zhang1, Tieli Zhou1
1 Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
2 Department of Microbiology, Infection&Immunity Program, Biomedicine Discovery Institute, Clayton 3800, Australia
3 Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
|Date of Web Publication||16-Mar-2017|
Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Liu H, Wilksch J, Li B, Du J, Cao J, Zhang X, Zhou T. Emergence of ST39 and ST656 extensively drug-resistant Klebsiella pneumoniae isolates in Wenzhou, China. Indian J Med Microbiol 2017;35:145-6
|How to cite this URL:|
Liu H, Wilksch J, Li B, Du J, Cao J, Zhang X, Zhou T. Emergence of ST39 and ST656 extensively drug-resistant Klebsiella pneumoniae isolates in Wenzhou, China. Indian J Med Microbiol [serial online] 2017 [cited 2019 Dec 11];35:145-6. Available from: http://www.ijmm.org/text.asp?2017/35/1/145/202343
The emergence and dissemination of carbapenemase-producing extensively drug-resistant (XDR) Klebsiella pneumoniae has limited effective therapies and posed a tremendous challenge to public health.,K. pneumoniae strains belonging to sequences types 11 (ST11), and ST258 are continually reported as pathogens that can cause epidemic infections in Asian and European countries. Nevertheless, ST39 and ST656 had been detected only in sporadic cases so far. Here, we investigated the molecular characteristics of two ST39 and ST656 XDR K. pneumoniae strains recovered from a teaching hospital in Wenzhou, China.
Two K. pneumoniae clinical isolates (FK541 and FK2180) were isolated from the First Affiliated Hospital of Wenzhou Medical University during 2014–2015. They were collected from sputum and blood samples of two senior male patients at Intensive Care Units, respectively. The modified Hodge test (MHT) was positive for FK541, ethylenediaminetetraacetic acid (EDTA)-disk synergy test was negative. Nevertheless, the MHT and EDTA-disk synergy test were both positive for FK2180. They were proven as carbapenemase producers by utilising the phenotypic methods. Antimicrobial susceptibility testing was conducted by the agar dilution method. Two isolates were resistant to ceftriaxone, ceftazidime, cefotaxime, imipenem, meropenem, ertapenem, levofloxacin, ciprofloxacin, tobramycin, gentamicin, amikacin, chloromycetin and fosfomycin, but remained susceptible to polymyxin B and tigecycline. Furthermore, polymerase chain reaction amplification and sequencing demonstrated that two strains harboured blakpc-2, blaCTX-M-9, blaTEM-1, blaSHV, rmtB and aac(6')-Ib-cr genes simultaneously, along with single nucleotide mutations within the quinolone resistance-determining regions for strain FK541 in GyrA (Ser83Ile and Asp87Gly) and ParC (Ser80Ile), and for strain FK2180 in GyrA (Ser83Ile) and ParC (Ser80Ile). Mutations within the gyrA and parC genes could confer increased resistance to quinolones. Taken together, the coexistence of multiple resistant genes in XDR K. pneumoniae isolates may contribute to high-level resistance to the majority of clinically available antimicrobial agents. Moreover, the plasmid location of the carbapenemase gene blaKPC-2 was manifested on an agarose gel following electrophoresis [Figure 1]a and Southern blot. A plasmid of ~54.2 kb in size for both strains was observed to hybridize to the blakpc-2 probe in a Southern blot [Figure 1]b, which could be transferred to Escherichia coli J53 through conjugation (transconjugants were designated as J541 and J2180). Moreover, other resistance gene, such as blaCTX-M-9 for FK541, was also transferred successfully. The results of blaCTX-M-9 and rmtB probes were shown in [Figure 1]c and [Figure 1]d. Susceptibility tests revealed that both the transconjugants exhibited resistance or decreased susceptibility to cephalosporins and carbapenems, compared to E. coli J53. These data displayed the resistance determinant was transferable among species. With regard to genotypic relatedness, multilocus sequence typing revealed that two KPC-2-producing K. pneumoniae strains were typed into two rare genotypes. Strain FK541 belonged to ST39 and strain FK2180 belonged to ST656. To the best of our knowledge, this is the first description of ST656 K. pneumoniae carrying blaKPC-2 in China.
|Figure 1: Plasmid analysis and southern blot hybridization of the two KPC-2-producing K. pneumoniae isolates and transconjugants. (a) Plasmid DNA of two Klebsiella pneumoniae isolates and transconjugants was separated by agarose gel electrophoresis; Escherichia coli V517 as the marker. (b) Southern blot hybridization of the gel with the blakpc probe. (c) Southern blot hybridization of the gel with the blaCTX-M-9 probe. (d) Southern blot hybridization of the gel with the rmtB probe.|
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In conclusion, our study certified that KPC-2-producing K. pneumoniae strains of ST39 and ST656 are emerging in Wenzhou, the two K. pneumoniae isolates harbouring plasmids carrying the blaKPC-2 gene can be transmitted among isolates by horizontal transfer. Effective surveillance should provide guidance on the utility of antimicrobial agents to treat XDR K. pneumoniae infections.
Financial support and sponsorship
This work was supported by research grants from the National Natural Science Foundation of China (no. 81171614), the Health Department of Zhejiang Province of the People's Republic of China (no. 2011KYA106) and Zhejiang Provincial Program for the cultivation of high-level innovative health talents.
Conflicts of interest
There are no conflicts of interest.
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