Objective　To analyze the sensitivity of carbapenem-resistant Enterobacteriaceae (CRE) producing different carbapenemases to antibacterial drugs, compare various detection methods of carbapenemases, and provide a technical basis for the clinical anti-infective treatment of CRE. Methods A total of 88 CRE strains isolated from clinical samples in a hospital in Nanchang, Jiangxi Province, from January 2021 to August 2022 were collected. MALDI-TOF MS was used for strain identification and Vitek 2-compact was used to detect their susceptibility to commonly used antibacterial drugs. The susceptibility of ceftazidime/avibactam and polymyxin B to CRE was detected by the broth microdilution method. The carbapenemase inhibitor enhancement test (EDTA-APB) was employed to screen for carbapenemase phenotypes, while polymerase chain reaction (PCR) method was used to detect five carbapenemase resistance genes: Klebsiella pneumoniae carbapenemases (blaKPC), New Delhi metallo-beta-lactamase-1 (blaNDM), Imipenem hydrolyzing β-lactamase (blaIMP), Metal β-lactamase of Verona integron (blaVIM), and Oxacillin-hydrolyzing carbapenemase (blaOXA-48-like). The consistency between carbapenemase phenotypes and gene results was compared. Results CRE infection was predominantly found in males (58 cases), with an average age of (63.4±14.2) years, mainly distributed in neurosurgery (26.1%, 23/88), the intensive care unit (17.0%, 15/88), and the rehabilitation department (15.9%, 14/88). The main sources of positive specimens were respiratory secretions (60.2%, 53/88), urine (21.6%, 19/88), and blood (5.7%, 5/88). The results of the drug susceptibility test showed that CRE had the highest resistance rate to cephalosporins and piperacillin/tazobactam, exceeding 95%, and the lowest resistance rate to tigecycline and polymyxin B, at 4.5% (4/88) and 1.1% (1/88), respectively. The results of the carbapenemase phenotype detection showed that the strains producing class A serine enzymes, class B metalloenzymes, and both class A and B carbapenemases accounted for 69.4% (61/88), 28.4% (25/88), and 1.1% (1/88), respectively. The results of PCR amplification of carbapenemase genes showed that the strains carrying class A resistance gene blaKPC, class B resistance gene blaNDM or blaIMP, and both blaKPC+NDM accounted for 70.5% (62/88), 28.4% (25/88), and 1.1% (1/88), respectively, with high consistency with enzyme phenotype results. The susceptibility rate of the strains carrying only blaKPC to ceftazidime/avibactam was 91.9% (57/62), while those carrying blaNDM or blaIMP were all highly resistant to ceftazidime/avibactam, accounting for 83.3% (25/30) of ceftazidime/avibactam-resistant strains. Conclusions The resistance mechanism of CRE strains to ceftazidime/avibactam is primarily due to the production of NDM-type metalloenzymes, while strains producing only KPC-type show higher sensitivity. Some ceftazidime/avibactam-resistant strains producing only KPC enzymes are caused by blaKPC-2 mutations. In addition, enzyme phenotype inhibition enhancement test and in vitro drug susceptibility test of ceftazidime/avibactam are recommended clinically to provide a basis for the rational selection of antibacterial drugs.

Objective To investigate the application valve of bFGF to improve the viability of trans-plantation flap in Wistar rat. Methods Forty-eight Wistar rats were randomly divided into two groups based on the age: group A,B(1.5 month old, every group was 12 rats) and group C,D (3 month old, every group was 12 rats). After an ischemic model completed, recombinant bovine basic fibroblast growth factor (rb-bFGF) was given to groups A and C in ischemie zone by vascularization flap injection and the equality of normal saline to groups B and D. 14 days postoperatively, the muscular tissue was sent for histology, the blood vessel density was calculated by image analysis, and positive VEGF was detected by immunohistochem-istry. Results The member of capillaries and positive VEGF were more in group A than that in B, and also were morein group C than D(P < 0.05), but there were not statistic difference between group A and C (P > 0.05). Conclusion Recombinant bovine bFGF can stimulate angiogenesis and improve the ischemie vascu-larization flap of rat, which is not associated with their age.