Tsukamurella pulmonis central venous catheter infection mimicking proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA)-associated vasculitis.

A 40-year-old Japanese woman, who underwent total thyroidectomy, had suffered from repeated episodes of fever and microscopic hematuria for 3 years, which had started 3 months after central venous port catheter insertion. On admission, she had malaise and low-grade fever, and was found to have microscopic hematuria, urinary red blood cell casts, multiple pulmonary nodules, and positivity of proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA), which were suggestive to the presence of ANCA-associated small vessel vasculitis. However, her blood culture and subsequent gene analysis revealed the positivity of Tsukamurella pulmonis, and she was diagnosed with Tsukamurella pulmonis bacteremia accompanying PR3-ANCA positivity. Her condition improved after the removal of the catheter and antibiotic treatment. Tsukamurella species are categorized to the order Actinomycetales and can be misidentified as other Actinomycetales without genetic analyses. This case illustrates that chronic Tsukamurella pulmonis infection can cause ANCA production and nephritis, which mimics ANCA-associated vasculitis. Thus, it is critical to diagnose these cases correctly to avoid misdiagnosis and inappropriate treatment, such as immunosuppressive treatment.

Detrimental Effect of Sintering Additives on Conducting Ceramics: Yttrium-Doped Barium Zirconate.

Y-doped BaZrO3 (BZY) is currently the most promising proton-conductive ceramic-type electrolyte for application in electrochemical devices, including fuel cells and electrolyzer cells. However, owing to its refractory nature, sintering additives, such as NiO, CuO, or ZnO are commonly added to reduce its high sintering temperature from 1600 °C to approximately 1400 °C. Even without deliberately adding a sintering additive, the NiO anode substrate provides another source of the sintering additive; during the co-sintering process, NiO diffuses from the anode into the BZY electrolyte layer. In this work, a systematic study of the effect of NiO, CuO, and ZnO on the electroconductive properties of BaZr0.8 Y0.2 O3-δ (BZY20) is conducted. The results revealed that the addition of NiO, CuO, or ZnO into BZY20 not only degraded the electrical conductivity but also resulted in enhancement of the hole conduction. Removal of these sintering additives can be realized by post-annealing in hydrogen at a mild temperature of 700 °C, but it is kinetically very slow. Therefore, the addition of NiO, CuO, and ZnO is detrimental to the electroconductive properties of BZY20, and significantly restrict its application as an electrolyte. The development of new sintering additives, new anode catalysts, or new methods for preparing BZY electrolyte-based cells is urgently needed.