The first case of chronic pulmonary Mycobacterium shigaense infection in an immunocompetent patient

Non-tuberculosis Mycobacterial Pulmonary Disease Caused by Mycobacterium kiyosense, a New Species

Non-tuberculosis mycobacterial (NTM) pulmonary disease (NTM-PD) is quite common, and newly identified species are being reported increasingly frequently thanks to advances in identification technologies. A 56-year-old woman had mild sputum production showed bronchiectasis with multiple small nodules, consistent with NTM-PD, on chest computed tomography. Mycobacterial species were isolated from the specimens; however, conventional methods could not identify the species. We conducted whole-genome sequencing and identified the NTM isolates as Mycobacterium kiyosense, a species newly registered in 2023 from Japan. She was diagnosed with NTM-PD caused by M. kiyosense and received watchful waiting.

Pulmonary disease caused by a newly identified mycobacterium: Mycolicibacterium toneyamachuris: a case report

BACKGROUND

Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is becoming a significant health burden. Recent advances in analysis techniques have allowed the accurate identification of previously unknown NTM species. Here, we report a case of NTM-PD caused by a newly identified mycobacteria in an immunocompetent patient.

CASE PRESENTATION

A 44-year-old woman was referred to our hospital due to the frequent aggravation of her chronic respiratory symptoms, with NTM-PD-compatible computed tomography findings. Unidentified mycobacterium was repeatedly isolated from respiratory specimens and we diagnosed her as NTM-PD of unidentified mycobacterium. Subsequent whole-genome analysis revealed that the unidentified mycobacterium was a novel mycobacterium genetically close to Mycolicibacterium mucogenicum. We started combination therapy with clarithromycin, moxifloxacin, amikacin, and imipenem/cilastatin, referring to drug sensitivity test results and observed its effect on M. mucogenicum infection. Her symptoms and radiological findings improved significantly.

CONCLUSION

We report a case of NTM-PD caused by a newly identified mycobacteria, Mycolicibacterium toneyamachuris, genetically close to M. mucogenicum. This pathogenic mycobacterium showed different characteristics from M. mucogenicum about clinical presentation and drug sensitivity. The clinical application of genomic sequencing will advance the identification and classification of pathogenic NTM species, and enhance our understanding of mycobacterial diseases.

Two New Cases of Pulmonary Infection by Mycobacterium shigaense, Japan

We report 2 case-patients in Japan with Mycobacterium shigaense pulmonary infections. One patient was given aggressive treatment and the other conservative treatment, according to distinctive radiologic evidence. A close phylogenetic relationship based on whole-genome sequencing was found between strain from the conservatively treated patient and a reference strain of cutaneous origin.