1.Clinical characteristic analysis and detection of bla KPC gene subtype variations in ST11-KL64 CRKP isolates based on whole genome sequencing
Chengcheng MA ; Na WANG ; Yuanli DUAN ; Rongrong YAN ; Tao YAN ; Qiuyan WANG ; Xuan TENG ; Kexue YU ; Zhou LIU
Chinese Journal of Laboratory Medicine 2025;48(9):1172-1178
Objective:To analyze the evolution of ceftazidime/avibactam (CZA) resistance phenotyes and clinical features of 11 ST11-KL64 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates carrying bla KPC. Methods:Eleven CRKP isolates, designated K01 to K11, obtained from infected liver transplant patients from June to September 2024 were retrospectively studied. Broth microdilution method, whole genome sequencing (WGS) and plasmid conjugation assays were employed to investigate the antimicrobial susceptibility, resistance mechanisms, and genetic structural characteristics of these CRKP isolates. Clinical data were simultaneously collected and organized to analyze the correlation between bla KPC gene mutations and the clinical efficacy of antimicrobial therapy. Results:All eleven isolates of CRKP exhibited multidrug resistance phenotypes. Among them, K01-K09 and K11 were sensitive to CZA and resistant to carbapenems, while K10 was resistant to CZA and displayed sensitivity or intermediate resistance to carbapenems. WGS analysis showed that all 11 CRKP isolates belonged to the ST11-KL64 clonal type. Among these isolates, the K01-K09 and K11 isolates carry the bla KPC-2 gene, whereas the K10 isolate carries the bla KPC-33 gene. A single nucleotide mutation in bla KPC-2 (G532T) resulted in a substitution of tyrosine (Y) for aspartic acid (D) at Ambler position 179 (D179Y), causing resistance of CRKP to CZA and reduced sensitivity to Imipenem and Meropenem. The conjugative plasmid was successfully constructed, and compared to the parental strain, its minimum inhibitory concentration (MIC) to CZA increased 32 folds. Clinical data revealed that the patient developed the bla KPC-33 mutation after 51 days of CZA treatment. Conclusions:The bla KPC-33 mutation following CZA treatment for CRKP infection exhibits a considerable delay. It is essential to dynamically monitor the evolution of CRKP resistance to ensure timely adjustment of therapeutic strategies in case of the occurrence of mutations such as bla KPC-33.
2.Cloning,expression,and functional analysis of capsule-specific depolymerase targeting carbapenem-resistant Klebsiella pneumoniae
Tao YAN ; Na WANG ; Qiuyan WANG ; Chengcheng MA ; Xuan TENG ; Kexue YU ; Honghua GE ; Zhou LIU
Acta Universitatis Medicinalis Anhui 2025;60(7):1251-1257
Objective To construct the K64 capsule depolymerase recombinant protein,Dep44,and investigate its potential application against carbapenem-resistant Klebsiella pneumoniae(CRKP)infections.Methods The de-polymerase-encoding phage vB_Kpn_HF1013(GenBank:PP803128)was isolated and genomically analyzed to screen for candidate depolymerases.The recombinant protein Dep44 was constructed and functionally verified for depolymerase activity.Dep44 sensitive range was validated and Dep44 antimicrobial activity was assessed by bio-film disruption and serum sterilization assays.Results The tail spike protein of phage vB_Kpn_HF1013 exhibited depolymerase activity and recombinant protein Dep44 specifically degraded K64 CRKP capsule.Biofilm eradication assays demonstrated that recombinant Dep44 at both 2 μg/mL and 10 μg/mL significantly disrupted bacterial bio-films relative to the control.Serum bactericidal assays showed that Dep44 exhibited synergistic activity with serum,dependent on the complement system,as Dep44 alone lacked bactericidal properties.Conclusion Dep44 effec-tively targets and degrades K64 CRKP capsule,disrupts biofilms,and enhances serum bactericidal activity,high-lighting its potential for managing K64 CRKP infections and clearing biofilms from medical devices.
3.Cloning,expression,and functional analysis of capsule-specific depolymerase targeting carbapenem-resistant Klebsiella pneumoniae
Tao YAN ; Na WANG ; Qiuyan WANG ; Chengcheng MA ; Xuan TENG ; Kexue YU ; Honghua GE ; Zhou LIU
Acta Universitatis Medicinalis Anhui 2025;60(7):1251-1257
Objective To construct the K64 capsule depolymerase recombinant protein,Dep44,and investigate its potential application against carbapenem-resistant Klebsiella pneumoniae(CRKP)infections.Methods The de-polymerase-encoding phage vB_Kpn_HF1013(GenBank:PP803128)was isolated and genomically analyzed to screen for candidate depolymerases.The recombinant protein Dep44 was constructed and functionally verified for depolymerase activity.Dep44 sensitive range was validated and Dep44 antimicrobial activity was assessed by bio-film disruption and serum sterilization assays.Results The tail spike protein of phage vB_Kpn_HF1013 exhibited depolymerase activity and recombinant protein Dep44 specifically degraded K64 CRKP capsule.Biofilm eradication assays demonstrated that recombinant Dep44 at both 2 μg/mL and 10 μg/mL significantly disrupted bacterial bio-films relative to the control.Serum bactericidal assays showed that Dep44 exhibited synergistic activity with serum,dependent on the complement system,as Dep44 alone lacked bactericidal properties.Conclusion Dep44 effec-tively targets and degrades K64 CRKP capsule,disrupts biofilms,and enhances serum bactericidal activity,high-lighting its potential for managing K64 CRKP infections and clearing biofilms from medical devices.
4.Clinical characteristic analysis and detection of bla KPC gene subtype variations in ST11-KL64 CRKP isolates based on whole genome sequencing
Chengcheng MA ; Na WANG ; Yuanli DUAN ; Rongrong YAN ; Tao YAN ; Qiuyan WANG ; Xuan TENG ; Kexue YU ; Zhou LIU
Chinese Journal of Laboratory Medicine 2025;48(9):1172-1178
Objective:To analyze the evolution of ceftazidime/avibactam (CZA) resistance phenotyes and clinical features of 11 ST11-KL64 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates carrying bla KPC. Methods:Eleven CRKP isolates, designated K01 to K11, obtained from infected liver transplant patients from June to September 2024 were retrospectively studied. Broth microdilution method, whole genome sequencing (WGS) and plasmid conjugation assays were employed to investigate the antimicrobial susceptibility, resistance mechanisms, and genetic structural characteristics of these CRKP isolates. Clinical data were simultaneously collected and organized to analyze the correlation between bla KPC gene mutations and the clinical efficacy of antimicrobial therapy. Results:All eleven isolates of CRKP exhibited multidrug resistance phenotypes. Among them, K01-K09 and K11 were sensitive to CZA and resistant to carbapenems, while K10 was resistant to CZA and displayed sensitivity or intermediate resistance to carbapenems. WGS analysis showed that all 11 CRKP isolates belonged to the ST11-KL64 clonal type. Among these isolates, the K01-K09 and K11 isolates carry the bla KPC-2 gene, whereas the K10 isolate carries the bla KPC-33 gene. A single nucleotide mutation in bla KPC-2 (G532T) resulted in a substitution of tyrosine (Y) for aspartic acid (D) at Ambler position 179 (D179Y), causing resistance of CRKP to CZA and reduced sensitivity to Imipenem and Meropenem. The conjugative plasmid was successfully constructed, and compared to the parental strain, its minimum inhibitory concentration (MIC) to CZA increased 32 folds. Clinical data revealed that the patient developed the bla KPC-33 mutation after 51 days of CZA treatment. Conclusions:The bla KPC-33 mutation following CZA treatment for CRKP infection exhibits a considerable delay. It is essential to dynamically monitor the evolution of CRKP resistance to ensure timely adjustment of therapeutic strategies in case of the occurrence of mutations such as bla KPC-33.
5.Multi-disciplinary team of human herpes virus-6B encephalitis after liver transplantation
Yafei GUO ; Jizhou WANG ; Zebin ZHU ; Cui CHEN ; Guoyan LIU ; Sen QUN ; Kexue DENG ; Dehao HUANG ; Lianxin LIU
Organ Transplantation 2021;12(4):465-
Objective To evaluate the role of multi-disciplinary team (MDT) in improving the diagnosis and treatment of human herpes virus-6B (HHV-6B) encephalitis after liver transplantation. Methods MDT consultation was delivered for one rare case of HHV-6B encephalitis after liver transplantation to establish an effective individualized treatment regime. Results On the 16 d after liver transplantation, the patient developed headache, and suddenly presented with unresponsiveness, unconsciousness, coma complicated with involuntary limb twitching on the 18 d. Blood ammonia level was increased. Brain CT scan showed cerebral ischemic changes. Electroencephalography prompted the epileptic seizure. After MDT consultation, the possibility of nervous system infection after liver transplantation was considered, and medication therapy was given to control the epileptic seizure. Cerebrospinal fluid examination via lumbar puncture hinted increased intracranial pressure. Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) of the cerebrospinal fluid demonstrated that the patient was tested positive for HHV-6B nucleic acid, which confirmed the diagnosis of HHV-6B encephalitis. The immunosuppressant regime was adjusted, intravenous ganciclovir was given for antiviral treatment, and active interventions were delivered to prevent and treat relevant complications. Epileptic seizure disappeared after 4 d, and neurological symptoms were significantly alleviated after 2 weeks. After 4-week antiviral treatment, the patient was tested negative for virology testing, and the neurological function was restored to normal. Conclusions HHV-6B encephalitis rarely occurs after adult liver transplantation, which is primarily associated with the virus reactivation after use of immunosuppressant. MDT pattern may be employed to deepen the understanding of the patient's condition, formulate more effective individualized treatment regime, and enhance the clinical efficacy and safety.
6.Evaluation of precision and accuracy of bone mineral densitometry
Yangyang DUANMU ; Ling WANG ; Yong ZHANG ; Kexue DENG ; Kai LI ; Na LI ; M Glen BLAKE ; Xiaoguang CHENG
Chinese Journal of Radiology 2021;55(4):359-364
Objective:To evaluate the short-term precision and accuracy of bone mineral density (BMD) measured with quantitative CT (QCT) and dual-energy X-ray absorptiometry (DXA) in multi-centre clinical research with a European spine phantom (ESP).Methods:From January 2016 to April 2020, totally 40 CT scanners (12 Siemens from Germany, 12 Philips from Netherlands, 9 GE from US, 5 Toshiba from Japan, 2 United Imaging from China) and 53 DXA instruments (34 GE Lunar from US, 14 Hologic from US, 5 Medlink from France) used in multi-centre in China were enrolled. The CT equipment came from 31 centers and DXA equipment from 32 centers.Using Mindways QCT software, the ESP was scanned 10 times on each instrument with repositioning using standardized spine protocols with QCT and DXA. The BMD value of the three lumbar vertebrae with low, medium, high density and the mean BMD value were measured. Accuracy was assessed by comparing BMD values measured on each device with the actual value of the phantom. Short-term precision was calculated as the root-mean-square standard deviation (RMS-SD) and root-mean-square standard deviation coefficient of variation (RMS-%CV) for the repeated measurements. The repeated measures variance analysis was used to compare the differences in BMD between different devices.Results:The differences in BMD values were statistically significant among different CT and DXA devices.The ranges of the accuracy measured by different QCT devices were 1.20% to 7.60% for Siemens, -1.83% to 0.20% for Philips, 1.18% to 13.20% for GE, -0.12% to 3.55% for Toshiba, -1.65% to 6.32% for United Imaging, 6.59% to 21.34% for GE Lunar, -6.65% to 5.45% for Hologic, and -6.97% to -0.68% for Medlink, respectively. The RMS-%CV of all vertebral BMD values measured by QCT and DXA ranged from 0.38% to 3.85%. The RMS-SD of QCT was 0.54 to 2.45 mg/cm 3, of DXA was 0.009 to 0.037 g/cm 2. The RMS-%CV values of each vertebral body measured by different QCT and DXA devices decreased with the increase of BMD, while the RMS-SD values showed the opposite tendency. Conclusions:Based on ESP, the QCT and DXA devices have significant differences in lumbar spine BMD measurement. Comparing the measurement results among different devices requires cross-calibration. Overall, the accuracy and short-term precision are within a reasonable range, which can be used for clinical follow-up observation. The short-term precision error and accuracy error range of QCT in evaluating the density of ESP were slightly smaller than those of DXA.
7.Clinical value of the combined detection of serum CEA, CA199, CA242, and CA724 in colorectal cancers
Journal of Chinese Physician 2016;18(3):422-424
Objective To explore the significance of serum carcinoembryonic antigen (CEA),carbohydrate antigen (CA) 199,CA242,and CA724 combined detection in the diagnosis of colorectal cancer.Methods The levels of CA724,CA242,CA199,and CEA in 112 cases of colorectal cancers,74 cases of colorectal benign lesion group,and 128 cases of healthy physical examination group were detected by chemiluminescence method.Results The levels of CEA,CA199,CA242,and CA724 in sera were significantly higher than those in colorectal cancer group (P < 0.05),and the difference between two groups was not significant (P > 0.05).In the clinical diagnosis of colon and rectal cancers,the sensitivity,specificity,and detection rate of CEA were 52.3%,93.5%,and 76.8%;CA199 was 46.9%,91.9%,and 73.6%;CA242 was 56.3%,94.6%,and 79.0%;and CA724 was 49.2%,93.0%,and 75.2%.The combined detection of CEA,CA199,CA242,and CA724 were 76.6%,96.2%,and 87.6%.Conclusions In the diagnosis of colorectal cancer,combined detection of serum CEA,CA199,CA242,and CA724 has more clinical value.than single detection,and can improve the diagnostic sensitivity and detection rate.
8.Crisis resource management training in anaesthesia
Liu SU ; Wu PENG ; Chen YI ; Lian XINYAN ; Wang KEXUE
Chinese Journal of Medical Education Research 2014;13(12):1196-1200
Anesthesia safety plays an important role in the medical safety of the perioperative.At present the medical institutions in many countries apply crew resource management model for training and assessment in anesthesiology,surgery and emergency.It emphasizes the training of nontechnical skills,called crisis resource management(CRM).This article analyzes the causes of human error incidents and preventive measures and introduces CRM principles in medical principles and anesthesia correlation and applications.CRM helps to foresee the crisis of environment and deal with the crisis source to ensure the safety of patients.
9.The interaction of TGF-β1 and IL-10 in the grafts of inbred mice with rejection of heart transplantation
Xianghui ZHANG ; Kexue WANG ; Zhiwei DING ; Yongjin WEN ; Nana LIU
Chinese Journal of Thoracic and Cardiovascular Surgery 2014;30(10):624-627
Objective The expression of TGF-β1 and IL-10 in the grafts of inbred mice with rejection of heart transplantation were studied and the interaction of them in the rejection of heart transplantation in inbred mice investigated.Methods Allografts were divided into 2 groups:control group (n =70),cyclosporin A-treated group (CsA group,n =70).Hearts from inbred BABL/c mice were transplanted into a cervical location in the other recipients and the survival time of the allografts was observed.The local expression of TGF-β1 and IL-10 was detected at day 1,3,7,11,14,21 by reverse transcription polymerase chain reaction(RT-PCT) respectively.Results The survival time of the allografts was (20.3 ± 1.7) days in control group,and(32.2 t 3.4) days in CsA group (P < 0.01).The levels of the two cytokines expression were up-regulated in CsA group.The up-regulation of TGF-β1 was closely correlated with the survival of the grafts.Conclusion The expression and production of the two cytokines is up-regulated probably cause of administ ration of cyclosporin A,and favorite to the heart graft survival,and action of these two cytokines are probably interrelated.
10.Exploration on the teaching reformation of anesthesiology
Su LIU ; Xiaolin MA ; Qiang CHEN ; Hengjiang GE ; Yi HU ; Kexue WANG
Chinese Journal of Medical Education Research 2011;10(6):747-749
In order to better match the teaching hours of clinical anesthesiology with the teaching content of modem anesthesia, the teachers must take full advantage of various supplementary teaching methods in the limited teaching hours to help enhance the students' enthusiasm in active learning, help the students concentrate on the crucial points and apply their knowledge and ultimately improve the teaching quality.

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