关键词: 中心静脉导管, 凝固酶阴性葡萄球菌, 药敏结果, 基因同源性, 脉冲场凝胶电泳

Abstract: Objective  To clarify the distribution and drug resistance characteristics of coagulase-negative staphylococcus floras in patients with long-term indwelling tunnel cuffed catheters in a single dialysis center, to verify the consistency of the multiple detection methods including bacterial culture, automated testing for bacteria (ATB), and pulsed field gel electrophoresis (PFGE) for the same specimen, and to distinguish the clinical significance of colonization, pre-infection and infection period of the strains, in order to provide references for precise prevention, control and stratified intervention.  Methods  A total of 216 hemodialysis patients with tunnel cuffed catheters admitted to the Dialysis Center of Civil Aviation General Hospital from January 2020 to January 2025 were recruited for this study. Specimens from their catheter-related areas and nasal cavities were collected, and were subjected to bacterial culture, ATB, drug sensitivity test, and PFGE for gene homology analysis. The significance of the identified strains was evaluated in conjunction with clinical symptoms.  Results  A total of 109 coagulase-negative staphylococcus strains (12.62%) were isolated, mainly from external neck skins covered with dressings (53 strains, 48.62%). Staphylococcus epidermidis accounted for 51.38% of the strains (56 strains). These coagulase-negative staphylococci were resistant to penicillin (91/109, 83.49%), but sensitive to tigecycline and vancomycin (109/109, 100%). The consistency of the detection methods was satisfied, with Kappa=0.89 for bacterial culture/ATB and Kappa=0.78 for culture/PFGE typing (Kappa≥0.75 was defined as good consistency). Among the 109 strains, 75.23% (82/109) were considered to be colonization, 22.02% (24/109) were attributed to the pathogens of pre-infection stage, and 2.75% (3/109) to the pathogens of infection stage. PFGE indicated the existence of cross-patient clonal transmission (homology rate 18.67%, 28/150) and self-cross-site colonization (homology rate 66.67%, 16/24).  Conclusion  Patients with tunnel cuffed catheters have a higher rate of coagulase-negative staphylococcal colonization. Multiple detection methods are helpful to check accuracy each other. Clinically, regular screening and stratified intervention can reduce the risk of infection. PFGE is suitable for routine homology characterization.

Key words: Tunneled cuffed catheter, Coagulase-negative staphylococcus, Drug sensitivity test, Gene homology, Pulsed field gel electrophoresis