Rapid diagnosis of disseminated Mycobacterium mucogenicum infection in formalin-fixed, paraffin-embedded specimen using next-generation sequencing: A case report.

BACKGROUND: Mycobacterium mucogenicum (M. mucogenicum) belongs to the group of rapidly growing Nontuberculous mycobacteria. This microorganism is associated with a wide spectrum of infectious diseases. Due to a low detection rate or the time required for conventional culture methodology, a rapid and broad-spectrum method is necessary to identify rare pathogens. CASE SUMMARY: A 12-year-old immunocompetent girl presented with painful masses for five months. The first mass was found in the right upper quadrant of the abdomen, and was about 1 cm × 1.5 cm in size, tough but pliable in texture, with an irregular margin and tenderness. An abscess gradually formed and ulcerated with suppuration of the mass. Three new masses appeared on the back one by one. Chest computed tomography showed patchy and streaky cloudy opacities in both lungs. Needle aspiration of the abscess was performed, but the smear and conventional culture were negative, and the pathological examination showed no pathogens. We then performed next-generation sequencing using a formalin-fixed, paraffin-embedded specimen to identify the pathogen. A significantly high abundance of M. mucogenicum was detected. The patient's abscesses gradually decreased in size, while inflammation in both lungs improved following 12-wk of treatment. No recurrence was observed four months after the end of the one-year treatment period. CONCLUSION: Next-generation sequencing is a promising tool for the rapid and accurate diagnosis of rare pathogens, even when using a formalin-fixed, paraffin-embedded specimen.