Mycobacterium colombiense sp. nov., a novel member of the Mycobacterium avium complex and description of MAC-X as a new ITS genetic variant

Martha I. Murcia, Enrico Tortoli, M. Carmen Menendez, Elia Palenque, Maria J. Garcia

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Forty-five mycobacterial strains isolated from 23 Colombian HIV-positive patients were identified as members of the Mycobacterium avium complex (MAC) and were characterized using different molecular approaches. Seven of the isolates showed characteristic features that allowed them to be differentiated from other members of the complex. The isolates had a novel 16S-23S rRNA internal transcribed spacer (ITS 1) gene sequence which is described as a new sequevar, MAC-X. All of the seven novel isolates gave a positive result with the MAC-specific AccuProbe (Gen-Probe), but tested negative for Mycobacterium avium and Mycobacterium intracellulare species-specific probes (64 and 100% of the isolates, respectively). The novel isolates could be differentiated phenotypically from other members of the MAC on the basis of the production of urease and by a consistent mycolic acid pattern. The novel isolates shared some characteristics with M. avium, such as the avium variant I (av-1) pattern of the hsp65 gene as determined by PCR restriction analysis and a positive PCR result for the mig (macrophage-induced) gene. However, the novel isolates showed a unique 16S rRNA gene sequence. DNA-DNA relatedness values, from 24 to 44%, confirmed the distinction of the novel isolates from other members of the MAC at the genetic level and their status as members of a separate species. The novel isolates are proposed as representatives of a novel species, Mycobacterium colombiense sp. nov., that is closely related to M. avium within the MAC. The type strain is 1OBT (=CIp 108962T =CECT 3035T)

Original languageEnglish
Pages (from-to)2049-2054
Number of pages6
JournalInternational Journal of Systematic and Evolutionary Microbiology
Issue number9
Publication statusPublished - Sep 2006

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology
  • Ecology, Evolution, Behavior and Systematics
  • Immunology


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