Mycobacterium kyorinense infection.

摘要: To the Editor: Mycobacterium kyorinense is a nonpigmented, slowly growing mycobacterium that was initially isolated in 2007 from patient with pneumonia Japan (1,2). The sequences of 16S rRNA, hsp65, and rpoB genes M. were closely related to, but different from, those type strains celatum branderi, 2 most phylogenetically species (1). Biochemical tests, such as for arylsulfatase activity, tellurite reduction, heat-stable catalase, also distinguish branderi. In our initial report, which this first recognized, we described 3 Japanese patients Recently, 1 additional case reported Brazil (3). Here describe 7 newly identified whose infection may have been caused by kyorinense. In reviewing characteristics these 11 (10 Brazil), found no apparent contacts among them. Nine had respiratory infections, lymphadenitis, arthritis (Table). Of these, 9 fulfilled criteria infections clinical significance (4) considered to harbor kyorinense. 4 died result infection. These data suggest belongs class nontuberculous mycobacteria are pathogenic humans substantial effects. Table Clinical infected antimicrobial susceptibility organism* Among 10 whom precise records available, treated first-line tuberculosis drugs, mainly rifampin, isoniazid, ethambutol, therapies ineffective all patients. Six received combination including macrolides fluoroquinolones, first- or second-line chemotherapy, subdued without recurrence 5 contrast, who did not receive sufficient therapy latter regimen eventually (3 patients) breast cancer (1 patient). MICs various drugs determined broth microdilution method For strains, MICs isoniazid relatively high, macrolides, aminoglycosides, quinolones low. Notably, rifampin remarkably high (>32 μg/mL) tested (Table). Direct sequencing rRNA gene, performed previously described, revealed 8 available isolates identical across entire sequenced interval (1,470 bp). sole exception strain Brazil, showed 4-bp substitution other Although sequences, heterogeneity at positions observed be heterogeneous previous investigation This observation might reflect presence copies has occasionally mycobacterial species, (5). Direct gene demonstrated locus. differed sequence 15 nt within codons 511–533. At amino acid level, changes synonymous residue 531. residue, Ser531 RpoB protein, replaced an Asp frequent location substitutions rifampin-resistant (6). Why almost exclusively clear. tendency largely reporting bias Japan. However, particular geographic distribution. context, it noteworthy characterized current study slightly Japan. It notable so far invariably resistant vitro testing. Rifampin appeared clinically patients, although definite efficacy cannot evaluated retrospective study. Analysis replacement aa 531 when compared protein. finding suggests inherently because structural features its Amino bacterial celatum, Borrelia burgdorferi, Spiroplasma citri (7–9). any case, understanding intrinsic resistance critical appropriately treating microorganism. On basis results study, recommend fluoroquinolones and/or aminoglycosides used treatment