[Tricuspid Valve Replacement for Isolated Tricuspid Valve Infective Endocarditis without Risk Factor].

A 78-year-old Japanese male with previous gastric cancer and untreated diabetes mellitus was admitted to hospital for persistent fever and leg edema. Blood culture was positive for Streptococcus angino'sus, and echocardiography showed isolated tricuspid valve infective endocarditis. Infection was controlled with intravenous antibiotics, but surgery was indicated because of persistent severe regurgitation and large vegetation of 15 mm in size. As the tricuspid valve anterior leaflet was extensively damaged, he underwent valve replacement using a bioprosthetic valve. The patient was discharged 25 days postoperatively with additional antibiotics, and he has been free from recurrent endocarditis for 6 months.

Creation of an experimental rearing environment for microbiome animal research using an individually ventilated cage system and bioBUBBLE enclosure.

To avoid microbial contamination risk, vinyl film isolators are generally used in animal microbiome experiments involving germ-free (GF) mice and/or gnotobiotic (GB) mice. However, it can take several months to gain expertise in operating the isolator competently. Furthermore, sterilization and sterility testing, which are essential for isolator preparation, can take more than 20 days. Hence, we built an experimental rearing environment that combines an individual ventilation cage system and a bioBUBBLE clean room enclosure to easily set up an experimental animal microbiome environment for animal facilities. In this work, a three-step evaluation was conducted. First, we examined whether GF mice can be maintained in this rearing environment without bacterial contamination. Next, we examined whether GF and GB mice can be maintained without cross-contamination in one individual ventilation cage rack. Finally, we tested whether GF mice can be maintained in a biological safety cabinet controlled by negative pressure. In our series of experiments, no microbial contamination occurred over more than 3 months. These results indicated that our rearing system that combines the individual ventilation cage and bioBUBBLE systems can be used not only for experiments with GF mice but also for Biosafety Level 2 experiments that handle bacteria. Our system can mitigate various disadvantages of using vinyl film isolators. In conclusion, we established an experimental method with improved working time and efficiency compared with those of the previous vinyl isolator method.