Metagenomic next-generation sequencing identifying a rare case of Mycobacterium xenopi discitis

Mycobacterium xenopi is a non-tuberculous mycobacterium (NTM) that sporadically causes infections in humans and can cause rare bone and joint infections in immunocompromised hosts with history of spinal surgery. This slow-growing mycobacterium takes 8-12 weeks to grow on culture. Metagenomic next-generation sequencing (MNGS) is a highly sensitive and specific plasma-based microbial cell-free DNA test that can detect M. xenopi weeks prior to culture growth. We present a case of M. xenopi lumbosacral discitis with presacral abscess in an immunocompromised woman without history of spinal surgery which was detected by MNGS 8 weeks prior to culture growth. The patient's discitis resolved with an M. xenopi-directed regimen of ethambutol, rifampin and azithromycin. This case illustrates the utility of next-generation sequencing tests in rapid diagnosis of rare and opportunistic infections, as compared with traditional diagnostic tests, with supporting contextual clinical and diagnostic findings.