Drug resistance and virulence characteristics of carbapenem-resistant Klebsiella pneumoniae carrying the blaKPC-2 gene
10.3760/cma.j.cn112309-20240729-00284
- VernacularTitle:携带 blaKPC-2基因碳青霉烯类耐药肺炎克雷伯菌的耐药及毒力特征
- Author:
Yongshi ZHAO
1
;
Yan ZHANG
;
Jian MAO
;
Yingxuan CHEN
;
Yaozhu YANG
;
Qiuling HUANG
;
Yan DU
;
Na DU
Author Information
1. 昆明医科大学第一附属医院医学检验科，云南省检验医学重点实验室，云南省医学检验临床医学研究中心，昆明 650032
- Publication Type:Journal Article
- Keywords:
Carbapenems;
Klebsiella pneumoniae;
Virulence genes;
Drug resistance gene;
Siderophore
- From:
Chinese Journal of Microbiology and Immunology
2025;45(8):671-679
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the drug resistance and virulence characteristics of KPC-2-producing carbapenem-resistant Klebsiella pneumoniae(CRKP). Methods:A total of 26 non-repeating CRKP strains clinically isolated from a Class Ⅲ hospital in Kunming from August 2021 to March 2022 were collected. Mass spectrometry and the VITEK 2 Compact system were used to identify the bacteria and perform drug susceptibility tests. PCR was used to amplify the drug resistance and virulence genes carried by the strains. These CRKP strains were divided into a hypervirulent CRKP(CR-hvKP) group and a CR-non-hvKP group according to the characteristic virulence genes of hypervirulent Klebsiella pneumoniae. The virulence phenotypes of CRKP were investigated by wire drawing test, serum resistance test and siderophore qualitative and quantitative tests. The whole genomes of CRKP-67 (a CR-hvKP strain) and CRKP-94 (a CR-non-hvKP strain) were sequenced by the Illumina high-throughput sequencing platform, to further analyze the drug resistance genes, virulence genes, and virulence plasmidds carried by the strains. Results:The drug sensitivity results indicated that all 26 strains were resistant to carbapenem, cephalosporins, fluoroquinolones and β-lactam/β-lactam inhibitor complexes. The resistance rates to amicacin, cotrimoxazole and gentamicin were 61.54%(6/26), 57.69%(15/26) and 73.08%(9/26), respectively. Regarding the drug resistance gene amplification results, the carrying rates of blaKPC-2, blaNDM-1, blaOXA-48, blaVIM, blaIMP, blaSME, blaSHV, blaCTX-M and blaTEM were 100.00%(26/26), 0, 0, 0, 0, 100.00%(26/26), 100.00%(26/26), 15.38% (4/26) and 73.08%(19/26), respectively. In the 26 strains, the carrying rates of toxic genes entB, entC, ureA, uge, wabG, ycf, irp1, irp2, mrkD, fimH and ybtS were 100.00%(26/26), while the carrying rates of virulence genes kfuB, iroN, aero, magA and alls were 0. The positive rate of string test was 66.7%(6/9) in the CR-hvKP group and 0 in the CR-non-hvKP group. The serum killing test showed a high sensitivity rate of 77.78%(7/9), a low sensitivity rate of 11.11%(1/9), and a serum resistance rate of 11.11%(1/9) in the CR-hvKP group. In the CR-non-hvKP group, the high sensitivity rate was 29.41%(5/17); the low sensitivity rate was 17.65%(3/17), and the serum resistance rate was 52.94%(9/17). There was no statistical significance between the two groups( P>0.05). The qualitative results of siderophore showed that all strains produced yellow chelating circles with slightly different color depth and size. The quantitative results of siderophore experiment showed that the average siderophore production level of CR-hvKP group was 40.74%, and that of CR-non-hvKP group was 28.21%. The level was higher in the CR-hvKP group than in the CR-non-hvKP group, and the difference was statistically significant( P<0.05). Whole-genome sequencing results showed that CRKP-67 was ST11 type and contained 3 plasmids. Among them, plasmid pCRKP-67-A carried a series of virulence genes, including iucABCD, iutA, rmpA, rmpA2, iroB and peg344, which were highly virulent characteristic genes. Plasmid pCRKP-67-B carried blaKPC-2, blaCTX-M, blaSHV, blaTEM and other drug-resistant genes. Plasmid pCRKP-67-C carried sul2, tetR, tetA and other drug-resistant genes. The CRKP-94 was of ST340 type and contained a drug-resistant plasmid carrying blaKPC-2, blaCTX-M, blaSHV, blaTEM and other drug-resistant genes. Conclusions:CRKP strains are highly resistant, and are only sensitive to a few antibiotics, and carry a variety of drug resistance genes. The main resistance mechanism to carbapenem antibiotics is the presence of the blaKPC-2 gene, which is located on the plasmids, which results in the spread of carbapenem resistance. The types and quantity of virulence genes carried by the CR-hvKP strain are more and greater respectively than those carried by the CR-non-hvKP strain. The co-existence of drug-resistant and virulence plasmids in CR-hvKP strains may lead to the co-transmission of high drug resistance and hypervirulence, which should be highly valued by relevant departments.
