Carbapenem-resistant hypermucoviscous Klebsiella pneumoniae clinical isolates from a tertiary hospital in China: Antimicrobial susceptibility, resistance phenotype, epidemiological characteristics, microbial virulence, and risk factors.
Hypervirulent and multidrug-resistant Klebsiella pneumoniae poses a significant threat to public health. We aimed to determine the common carbapenemase genotypes and the carriage patterns, main antibiotic resistance mechanisms, and in vitro susceptibility of clinical isolates of carbapenem-resistant K. pneumoniae (CRKP) to ceftazidime/avibactam (CZA) for the reasonable selection of antimicrobial agents and determine whether hypermucoviscous (HMV) phenotype and virulence-associated genes are key factors for CRKP colonization and persistence. Antibiotics susceptibility of clinical CRKP isolates and carbapenemase types were detected. CRKP isolates were identified as hypermucoviscous K. pneumoniae (HMKP) using the string test, and detection of virulence gene was performed using capsular serotyping. The bla KPC-2, bla NDM, bla IMP, and/or bla OXA-48-like were detected in 96.4% (402/417) of the isolates, and the bla KPC-2 (64.7%, 260/402) was significantly higher (P<0.05) than those of bla NDM (25.1%), bla OXA-48-like (10.4%), and bla IMP (4.2%). Carriage of a single carbapenemase gene was observed in 96.3% of the isolates, making it the dominant antibiotic resistance genotype carriage pattern (P < 0.05). Approximately 3.7% of the isolates carried two or more carbapenemase genotypes, with bla KPC-2 + bla NDM and bla NDM + bla IMP being the dominant multiple antibiotic resistance genotype. In addition, 43 CRKP isolates were identified as HMKP, with a prevalence of 10.3% and 2.7% among CRKP and all K. pneumoniae isolates, respectively. Most clinical CRKP isolates were isolated from elderly patients, and carbapenemase production was the main mechanism of drug resistance. Tigecycline and polymyxin B exhibited exceptional antimicrobial activity against CRKP isolates in vitro. Furthermore, bla KPC-2, bla NDM, and bla OXA-48-like were the main carbapenemase genes carried by the CRKP isolates. CZA demonstrated excellent antimicrobial activity against isolates carrying the single bla KPC-2 or bla OXA-48-like genotype. Capsular serotype K2 was the main capsular serotype of the carbapenem-resistant HMKP isolates. Survival rates of Galleria mellonella injected with K. pneumoniae 1-7 were 20.0, 16.7, 6.7, 23.3, 16.7, 3.3, and 13.3, respectively. Therefore, worldwide surveillance of these novel CRKP isolates and carbapenem-resistant HMKP isolates as well as the implementation of stricter control measures are needed to prevent further dissemination in hospital settings.
Wang Q
，Chen M
，Ou Q
，Zheng L
，Chen X
，Mao G
，Fang J
，Jin D
，Tang X
... -
《Frontiers in Cellular and Infection Microbiology》
Dissemination of Carbapenemases (KPC, NDM, OXA-48, IMP, and VIM) Among Carbapenem-Resistant Enterobacteriaceae Isolated From Adult and Children Patients in China.
This study aimed to investigate the dissemination and characteristics of blaKPC, blaNDM, blaOXA-48-like , blaIMP, and blaVIM among the carbapenem-resistant Enterobacteriaceae (CRE) strains isolated from adult and children patients. A total of 935 non-duplicate CRE strains were collected from 36 hospitals in 24 provinces or cities across China from 2016 to 2018. Antimicrobial susceptibility testing was performed by broth microdilution method and carbapenemase genes blaKPC, blaNDM, blaOXA-48-like , blaIMP, and blaVIM were screened by PCR and confirmed by DNA sequencing. Overall, carbapenemases were produced in 97.4% (911/935) of CRE strains, including KPC-2 (51.6%, 482/935), NDM (35.7%, 334/935), and OXA-48-like carbapenemases (7.3%, 68/935). Overall, the most prevalent carbapenemase gene was blaKPC-2 among Klebsiella pneumoniae (64.6%, 457/709) and the CRE strains isolated from adult patients (70.3%, 307/437), and blaNDM among Escherichia coli (96.0%, 143/149) and the CRE strains from children (49.0%, 247/498). The blaOXA-232-positive carbapenem-resistant K. pneumoniae (9.3%, 66/709) were all isolated from children. Sixteen strains were positive for blaIMP and 9 strains produced multiple carbapenemases. No strain was positive for blaVIM. Most of the CRE strains (>90%) were resistant to cephalosporins and carbapenems, more than half (>50%) were resistant to aminoglycosides and fluoroquinolones, but the majority (95.8 and 98.4%) were susceptible to polymyxin B and tigecycline. Ceftazidime-avibactam showed excellent in vitro activity against blaKPC-2 and blaOXA-48-like positive strains (100% susceptible). In China, KPC-2, NDM, and OXA-48-like carbapenemases were predominant among CRE clinical isolates. The most prevalent carbapenemase gene was blaKPC-2 among K. pneumoniae isolates from adult patients, and blaNDM among E. coli isolates from children.
Han R
，Shi Q
，Wu S
，Yin D
，Peng M
，Dong D
，Zheng Y
，Guo Y
，Zhang R
，Hu F
，China Antimicrobial Surveillance Network (CHINET) Study Group
... -
《Frontiers in Cellular and Infection Microbiology》
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