Novel Mycobacterium avium Complex Species Isolated From Black Wildebeest (Connochaetes gnou) in South Africa

Phenotypic and molecular characterisation of a novel species, Mycobacterium hubeiense sp., isolated from the sputum of a patient with secondary tuberculosis in Hubei of China

A new fast-growing mycobacterium, designated strain QGD101^T, was isolated from the sputum of an 84-year-old man suspected of tuberculosis in Wuhan Medical Treatment Center, Hubei, China. This strain was a gram-staining-negative, aerobic, non-spore-forming and catalase-positive bacterium, which was further identified as the NTM by PNB and TCH tests. The moxifloxacin and levofloxacin exhibited strong suppressing function against QGD101^T with MIC values of 0.06 and 0.125 µg/ml after drug susceptibility testing of six main antimicrobial agents on mycobacteria. Based on the sequence analysis of 16S rRNA, rpoB, hsp65 and 16S-23S rRNA internal transcribed spacer, the strain QGD101^T could not be identified to a species level. Mycobacterium moriokaense ATCC43059^T that shared the highest 16S rRNA gene sequence similarity (98%) with strain QGD101^T was actually different in genomes average nucleotide identity (78.74%). In addition, the major cellular fatty acids of QGD101^T were determined as C18:1ω9c, C16:0 and C18:2ω6c. The DNA G + C content was 64.9% measured by high performance liquid chromatography. Therefore, the phenotypic and genotypic characterisation of this strain led us to the conclusion that it represents a novel species of mycobacteria, for which the name Mycobacterium hubeiense sp. nov. (type strain QGD101^T = CCTCCAA 2017003^T = KCTC39927^T) was proposed. Thus, the results of this study are very significant for the clinical diagnosis of tuberculosis and future personalised medicine.

First report of nodular skin lesions caused by Mycobacterium nebraskense in a 9-year-old cat

Case summary

A 9-year-old cat was referred with multiple, raised, ulcerative skin nodules in the region of the neck and dorsal head. Histopathological findings of a biopsied nodule were granulomatous dermatitis and panniculitis without multinucleated giant cells or caseous necrosis. In addition, by Ziehl–Neelsen staining numerous acid-fast intracellular bacilli were observed within the lesions. Mycobacterial culture showed growth of rough scotochromogenic colonies after 3 weeks of incubation. Molecular characterisation of the isolate identified Mycobacterium nebraskense as the cause of the infection. No phenotypic resistance was detected for the antimycobacterial agents tested. The cat was successfully treated with a combination of surgical excision and a 12 week course of antimicrobial therapy, including rifampicin combined with clarithromycin.

Relevance and novel information

To our knowledge, this is the first documented case of mycobacterial granulomatous dermatitis and panniculitis due to M nebraskense infection in a cat. The successful surgical and antimycobacterial treatment regimen is described.