First case report of prosthetic valve endocarditis caused by Mycobacterium wolinskyi.

To date, only 26 cases of Mycobacterium wolinskyi infections have been reported in humans. We herein report a first case of prosthetic valve endocarditis due to this organism after cardiovascular surgery. An 82-year-old man presented with repeat episodes of syncope and fever after aortic valve replacement, mitral valve replacement, left atrial appendage closure, and pulmonary vein isolation. Blood cultures maintained in aerobic bottles were repeatedly positive after 90-100 hours, and Gallium scan revealed abnormal accumulations in the sternum and left testis. While colonies formed by culturing the fluid of the parasternal area and blood cultures revealed gram-positive rods, we could not analyze the colony using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF). M. wolinskyi was finally identified on 16S rRNA, hsp65, and rpoB gene sequencing. We treated the patient with multiple antimycobacterial drugs, i.e., amikacin, imipenem, and clarithromycin for 6 weeks, which was changed to oral ciprofloxacin and minocycline for 12 months. This case highlights the need to consider rapidly growing mycobacteria, including M. wolinskyi, if chronic fever persists from weeks to months after surgery, the blood culture is positive, and the organism is not identified. In addition, sequencing the 16S rRNA, hsp65, and rpoB genes is essential for diagnosis.

Slowly progressive insulin-dependent (type 1) diabetes positive for anti-GAD antibody ELISA test may be strongly associated with a future insulin-dependent state.

Slowly progressive insulin-dependent (type 1) diabetes mellitus (SPIDDM), believed to be caused by ß-cell destruction through islet-cell autoimmunity, gradually progresses to an insulin-dependent state over time. Although the presence of anti-glutamic acid decarboxylase antibody (GADA) is required for the diagnosis of SPIDDM, a recent change in the GADA assay kit from radioimmunoassay (RIA) to enzyme-linked immunosorbent assay (ELISA) yields mismatched GADA test results between the two kits, leading to confusion in understanding the pathological conditions of SPIDDM in Japan. Thus, this study aimed to clarify the difference in the clinical characteristics of GADA-ELISA-positive and GADA-ELISA-negative patients originally diagnosed as SPIDDM by GADA-RIA test. As a result, 42 of 63 original GADA-RIA-positive SPIDDM patients (66.7%) were found to be GADA-ELISA-positive, whereas the remaining 21 patients (33.3%) were found to be GADA-ELISA-negative. In patients with shorter disease duration, GADA-ELISA-positive patients showed significantly lower serum C-peptide levels than GADA-ELISA-negative patients. Meanwhile, in patients with longer disease duration, serum C-peptide levels were comparably decreased in GADA-ELISA-positive and GADA-ELISA-negative patients. A significant inverse correlation between serum C-peptide level and disease duration was observed in GADA-ELISA-negative patients, but not in GADA-ELISA-positive patients, suggesting that insulin secretory capacity may be gradually impaired over time also in GADA-ELISA-negative SPIDDM patients. In conclusion, physicians should be aware that GADA-ELISA-positive SPIDDM may be strongly associated with a future insulin-dependent state. Meanwhile, physicians should be careful in treating GADA-ELISA-negative SPIDDM patients diagnosed as type 2 DM, and cautiously follow the clinical course, in accordance with SPIDDM.