1.Drug resistance and virulence characteristics of carbapenem-resistant Klebsiella pneumoniae carrying the blaKPC-2 gene
Yongshi ZHAO ; Yan ZHANG ; Jian MAO ; Yingxuan CHEN ; Yaozhu YANG ; Qiuling HUANG ; Yan DU ; Na DU
Chinese Journal of Microbiology and Immunology 2025;45(8):671-679
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.
2.Drug resistance and virulence characteristics of carbapenem-resistant Klebsiella pneumoniae carrying the blaKPC-2 gene
Yongshi ZHAO ; Yan ZHANG ; Jian MAO ; Yingxuan CHEN ; Yaozhu YANG ; Qiuling HUANG ; Yan DU ; Na DU
Chinese Journal of Microbiology and Immunology 2025;45(8):671-679
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.
3.Effect of oral fish oil on wound healing in patients with diabetic foot ulcers:a randomized,double-blind,placebo-controlled study
Hao ZHANG ; Jing XU ; Qiang TONG ; Mengran SHI ; Min WANG ; Yingxuan DU ; Yuan WANG ; Chunlin ZHANG ; Jiawei LIU ; Xiaoqin GUO ; Xinyu LIANG ; Jian WANG
Chongqing Medicine 2024;53(5):669-676
Objective To investigate the effect of oral fish oil on wound healing and related indexes in patients with diabetic foot ulcer(DFU).Methods A randomized,double-blind,placebo-controlled design was used to recruit 68 patients with DFU aged 18-80 years old in the hospital,and the baseline clinical data of the patients were collected.The patients were randomly divided into experimental group(32 cases,fish oil soft capsule,3 g/d)and control group(33 cases,corn oil soft capsule,3 g/d)by random number generated by Ex-cel,and the intervention lasted for 12 weeks.The primary endpoints included the proportion of complete wound healing and healing area≥50%.The secondary endpoints included wound area,healing time,inflamma-tion index,glucose metabolism index,nutrition related index and wound reinfection.Additionally,the influen-cing factors of wound healing were analyzed.Results After intervention,the proportion of complete wound healing and healing area≥50%in the experimental group was significantly higher than that in the control group(P=0.007,0.039).In the subjects with complete wound healing,the mean healing time in the experi-mental group was shorter than that in the control group,but the difference was not statistically significant(P=0.132).The reduction area of wound area in the experimental group was significantly larger than that in the control group(P=0.045).The decrease of interleukin(IL)-6 and IL-8 in the experimental group was significantly higher than that in the control group(P<0.05).There was no significant difference in the reduc-tion of C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),neutrophil-to-lymphocyte ratio(NLR),glycated hemoglobin A1c(HbA1c)and platelet-to-lymphocyte ratio(PLR)between the two groups(P>0.05).The improvement of prealbumin(PA)in the experimental group was higher than that in the control group,but the difference was not statistically significant(P>0.05).Multivariate logistic regression analysis showed that oral fish oil intervention(OR=6.771,95%CI:1.787-25.652),HbA1c(OR=4.149,95%CI:1.026-16.770)and ulcer type(OR=4.319,95%CI:1.026-18.173)were the influencing factors of wound healing(P<0.05).Conclusion Oral fish oil promotes wound healing in patients with DFU,which may be re-lated to improving the level of chronic inflammation in the body.
4.Visualization Analysis on Research Hotspots and Frontier of Wumei Pills
Yingxuan HU ; Shuang ZHU ; Shihua WANG ; Yuan DU ; Xinlong LI
Chinese Journal of Information on Traditional Chinese Medicine 2024;31(2):78-83
Objective To summarize the research status and hotspots of Wumei Pills;To provide ideas and methods for the follow-up research of Wumei Pills.Methods Related literature about Wumei Pills was retrieved from CNKI,VIP,Wanfang Data and CBM from the establishment of the databases to January 12,2023.The publication time,author,author unit and keywords were collected and extracted through NoteExpress 3.0 software to manage bibliographic data.VOSviewer 1.6.18 software was used to conduct co-occurrence and clustering analysis,and construct keyword time superposition network.Results After screening,a total of 2 105 articles were included,involving 3 554 authors,such as Yan Shuguang,Fan Heng,and Hui Yi.They were from 1 135 units,such as Dongzhimen Hospital of Beijing University of Chinese Medicine,Shandong University of Traditional Chinese Medicine and Beijing University of Chinese Medicine.The included articles contained 2 565 keywords,which appeared 7 061 times,and the research involved 4 main directions:digestive system diseases(ulcerative colitis),study on TCM classics(Shang Han Za Bing Lun),medical cases and experience,and biliary ascariasis.The hotspots of Wumei Pills were scattered in recent years.Six meridian disease to appear,opening and closing pivots,intestinal microbiota,serum inflammatory factors and insomnia were research hotspots in recent 3 years.Conclusion The research of Wumei Pills mainly focus on the research of digestive system diseases,TCM classics,medical cases and experience,and biliary ascariasis.Theoretical research of TCM and mechanism research possibly become new hotspots of this field.
5.Non-enterotoxin-producing Bacteroides fragilis inhibits TNF-α-induced inflammatory response in colonic epithelial cells by down-regulating the NF-κB signaling pathway
Qiuyue HE ; Qiuling HUANG ; Jian MAO ; Yongshi ZHAO ; Yingxuan CHEN ; Yan ZHANG ; Yan DU
Chinese Journal of Microbiology and Immunology 2024;44(10):829-837
Objective:To investigate the mechanism by which non-enterotoxin-producing Bacteroides fragilis (NTBF) inhibits TNF-α-induced inflammatory responses in human normal colonic epithelial cells hcoEPIC, and explore new probiotic therapies for the prevention and treatment of colitis. Methods:The co-culture system of NTBF and hcoEPIC cells was established, and the adhesion and invasion ability of NTBF were detected, respectively. TNF-α was added to induce cellular inflammation after 4 h of co-culture of NTBF and hcoEPIC cells, and cell survival and apoptosis were detected by the CCK-8 assay and the AnnexinⅤ-FITC/PI assay respectively after 24 h. Key proteins of the NF-κB signalling pathway in hcoEPIC cells in different treatment groups were detected by Western blot and RT-qPCR, and the expression of downstream cytokines of this pathway incluing IL-1β, TNF-α and IL-10 were detected by ELISA. The effect of NTBF intervention on dextran sodium sulfate(DSS)-induced colitis mice was assessed by in vivo animal experiments. Results:NTBF adhered to hcoEPIC cells, and was non-toxic to the cells. Compared with control group, NTBF treatment alone did not affect cell survival and apoptosis of hcoEPIC cells ( P>0.05), but significantly reduced cell damage and apoptosis induced by TNF-α ( P<0.05); Compared with the TNF-α treatment alone group, the expression levels of p-NF-κB p65 and p-IκBα protein as well as NF-κB and IκBα mRNA were significantly reduced ( P<0.05); the production of IL-1β and TNF-α in the cell supernatant was reduced and the release of IL-10 was increased ( P<0.05). Animal experiments demonstrated that NTBF was indeed effective in alleviating DSS-induced colitis in ulcerative colitis model mice, which was mainly manifested by inhibiting weight loss, lowering DAI scores, improving colonic shortening, and attenuating colonic pathological damage in colitis-induced mice. Conclusions:NTBF may inhibit TNF-α-induced inflammatory responses in colonic epithelial cells by down-regulating the NF-κB pathway.

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