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.

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.

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.

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.

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.

Objective To study the changes of AKP activity and its cytochemistry position during liver regeneration following partial hepatectomy. Methods Using colorimetry to analyze AKP activity; using non-denatured electrophoresis technique to analyze the kinds and activity of AKP; using electron microscope cytochemistry to analyze its position. Results During liver regeneration, AKP activity had two peaks at 16*!h and 19*!h and followed by decline dramatically; Three hepatic-derived AKP isoenzymes were detected, and 180*!kD AKP appeared only in liver regeneration; AKP appeared in different part with the process of liver regeneraion.Conclusion AKP plays an important role in liver regeneration and it may involve in cell metabolism, material transportation, DNA synthesis and cell differentation.