Study on the features of Clostridioides difficile infection among diarrhea patients in Kunming from 2018 to 2020 / 中华流行病学杂志

Objective: We analyze the characteristics of Clostridioides difficile (C. difficile) infection among diarrhea patients in Kunming from 2018 to 2020 and provide evidence for follow-up surveillance and prevention. Methods: A total of 388 fecal samples of diarrhea patients from four sentinel hospitals in Yunnan Province from 2018 to 2020 were collected. Real-time quantitative PCR was used to detect the fecal toxin genes of C. difficile. The positive fecal samples isolated the bacteria, and isolates were identified by mass spectrometry. The genomic DNA of the strains was extracted for multi-locus sequence typing (MLST). The fecal toxin, strain isolation, and clinical patient characteristics, including co-infection with other pathogens, were analyzed. Results: Among the 388 fecal samples, 47 samples with positive reference genes of C. difficile were positive, with a total positive rate of 12.11%. There were 4 (8.51%) non-toxigenic and 43 (91.49%) toxigenic ones. A total of 18 strains C. difficile were isolated from 47 positive specimens, and the isolation rate of positive specimens was 38.30%. Among them, 14 strains were positive for tcdA, tcdB, tcdC, tcdR, and tcdE. All 18 strains of C. difficile were negative for binary toxins. The MLST results showed 10 sequence types (ST), including 5 strains of ST37, accounting for 27.78%; 2 strains of ST129, ST3, ST54, and ST2, respectively; and 1 strain of ST35, ST532, ST48, ST27, and ST39, respectively. Fecal toxin gene positive (tcdB+) results were statistically associated with the patient's age group and with or without fever before the visit; positive isolates were only statistically associated with the patient's age group. In addition, some C. difficile patients have co-infection with other diarrhea-related viruses. Conclusions: The infection of C. difficile in diarrhea patients in Kunming is mostly toxigenic strains, and the high diversity of strains was identified using the MLST method. Therefore, the surveillance and prevention of C. difficile should be strengthened.

Molecular Typing and Drug Resistance of Salmonella Typhimurium in Yunnan Province / 昆明医科大学学报

Objective To understand the molecular typing and drug resistance of Salmonella typhimurium in Yunnan Province, to provide scientific basis for preventing and controlling diseases caused by Salmonella typhimurium. Methods Molecular typing was carried out according to Salmonella PFGE typing technology published by Pulse Net China. The MIC value of the drug sensitive plate was obtained from the analysis of the instructions, and the results of S, I and R were obtained according to the corresponding standards of CLSI.Results The 68 strains salmonella typhimurium in Yunnan Province showed 53 types of PFGE. The drug resistance rate of the 68 strains of salmonella typhimurium was the highest for the compound sulfonamide (SXT), 45.59％, and the most sensitive to imipenem (IMP), among which one strain was resistant to 11 of the14 antibiotics. Conclusion The molecular typing of salmonella typhimuriumin in Yunnan province is diverse.Compound sulfonamide is the most resistant antibiotic of Salmonella typhimurium in this region. Multiple drug resistance of Salmonella typhimurium in this region is atypical.

Design and 3D finite element analysis of personalized ankle prosthesis / 医用生物力学

Objective To propose a personalized design of anatomic ankle prosthesis that can avoid and reduce the high failure rate and risk of ankle prosthesis in clinic. Methods The 3D finite element non-linear model of normal human ankle system was established and verified. The anatomic ankle prosthesis was then designed to simulate total ankle replacement, and the 3D finite element model with both the prosthesis and ankle system was established. The biomechanical characteristics of this prosthesis were calculated and analyzed after gait loads were applied. Results For the normal ankle system, the maximum plantar contact stress was 214.6 kPa and the maximum Von Mises stress of foot bone was 8.96 MPa. The reliability of the normal ankle system model was verified by comparing the simulated results with those reported by literature. After the prosthesis implantation, the simulated maximum Von Mises stresses of talus prosthesis, tibial UHMWPE liner, tibial prosthesis were 23.88, 19.24 and 73.01 MPa, respectively. The stress of the ankle prosthesis increased drastically compared with that of normal ankle system. Conclusions The comparison results by finite element analysis examine the feasibility of the personalized ankle prosthesis, and provide references for optimization of prosthesis design and its clinical application.