Case report of the first cured patient with Mycobacterium Chimaera infection following cardiac valve replacement in the mainland of China.

BACKGROUND: Mycobacterium chimaera infections subsequent to cardiac surgery are related to contaminated heater-cooler devices, with high mortality. Nevertheless, few studies have been reported in Asia. CASE PRESENTATION: We described the case of a 55-year-old man with Mycobacterium chimaera infection following cardiac surgery in the mainland of China. He was diagnosed with endocarditis caused by Mycobacterium chimaera subsequent to open heart surgery. Metagenomic next-generation sequencing (mNGS) and 16S rRNA gene PCR analysis were used to identify potential pathogens. The patient underwent redo valve replacement surgery and received combination therapy with azithromycin, ethambutol, linezolid, and amikacin. No signs of relapse were observed during the 11-month follow-up visit. CONCLUSIONS: This is the first documented case of Mycobacterium chimaera infection following cardiac surgery in the mainland of China and the first documented transnational imported case worldwide. Moreover, mNGS is a novel diagnostic technology that can guide antimicrobial therapy prior to obtaining fluid/tissue culture results for Mycobacterium chimaera, providing a new approach for the detection of potential Mycobacterium chimaera infection.

Alteration of parasympathetic/sympathetic ratio in the infarcted myocardium after Schwann cell transplantation modified electrophysiological function of heart: a novel antiarrhythmic therapy.

BACKGROUND: Neural remodeling after myocardial infarction (MI) may cause fatal ventricular arrhythmia. Schwann cells (SCs), which are important for neurogenesis, are dramatically reduced after MI. We investigated the feasibility of modifying nervous system regeneration after MI and the efficacy by which it may prevent ventricular arrhythmia following SC transplantation. METHODS AND RESULTS: Immediately after creation of MI, syngenic Lewis rats were randomized into cell transplantation (n=80) and control groups (n=72). SCs were isolated from sciatic nerves, and 5×10(6) cells were intramyocardially injected into the infarct region. Expression levels of myocardial nerve growth factor, vascular endothelial growth factor, growth-associated protein 43, connexin 43, and laminin in the SC group were significantly higher than control at 7 and 14 days after cell transplantation. Immunohistochemical staining illustrated increases in sympathetic and parasympathetic nerves in both groups. However, SC transplantation significantly increased the parasympathetic/sympathetic ratio at 14 days after cell injection. Dynamic electrocardiography and programmed electric stimulation were also performed. The SCs significantly decreased the low-/high-frequency ratio and arrhythmia score of programmed electric stimulation-induced ventricular arrhythmia at 2 weeks after cell injection. However, SCs did not restore heart function. CONCLUSIONS: Transplanted SCs in the infarcted myocardium secrete multiple biological molecules, which alter the ratio of parasympathetic/sympathetic nerve density to normalize irritable myocardium. SC transplantation might be a novel cell-based antiarrhythmic therapy following MI.