Summary auto-generated
This study characterized Mycobacterium celatum strains from three countries using molecular methods to clarify relationships between three previously identified sequence types. Researchers analyzed 18 M. celatum strains using restriction fragment length polymorphism (RFLP), pulsed-field gel electrophoresis (PFGE), and PCR-restriction analysis of the hsp-65 gene. A new insertion element, IS1407, belonging to the IS256 family, was identified and sequenced from M. celatum type 1 strains. The element was absent in type 2 strains. RFLP analysis revealed that M. celatum type 1 and type 3 strains contained three to four copies of IS1407 in identical genomic positions, suggesting close genetic relatedness between these types. PFGE analysis showed type 1 and type 3 strains had consistent, homogeneous restriction patterns, while type 2 strains displayed polymorphic patterns. Additionally, extrachromosomal elements ranging from 20 to 180 kb were detected in type 2 and type 3 strains but not in type 1 strains. The results confirm that M. celatum types 1 and 3 are very similar and likely represent a distinct genomic cluster from type 2, supporting the proposal that type 2 may represent a separate species.
Key findings
- IS1407, a new insertion sequence belonging to the IS256 family, was identified only in M. celatum types 1 and 3, absent in all type 2 strains
- M. celatum type 1 and type 3 strains produced identical molecular patterns and are closely related; type 1 strains contain three to four copies of IS1407 at identical chromosomal positions
- M. celatum type 2 strains display significantly greater genomic polymorphism by PFGE analysis compared to the homogeneous type 1 and 3 strains
- Extrachromosomal elements (20-180 kb) were detected in type 2 and type 3 strains but were absent from all type 1 strains
- The molecular data support the hypothesis that M. celatum types 1 and 3 represent a single genomic cluster while type 2 likely constitutes a separate species
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
Genomic analyses of 18 Mycobacterium celatum strains obtained from different patients in three countries (United States, United Kingdom, and France) were performed; the methods used in this study were restriction fragment length polymorphism (RFLP) analysis, pulsed-field gel electrophoresis (PFGE) analysis, and PCR restriction analysis (PRA) of the hsp-65 gene. A new insertion sequence, IS1407(GenBank accession no. X97307), belonging to the IS256 family, was identified in M. celatum type 1 strains and was characterized by sequencing. When a probe for Mycobacterium xenopi IS1395-like sequences was used, the RFLP analysis of M. celatum type 1 strains revealed that they contained three or four copies of IS1407 in identical genomic positions, while this element was absent in all M. celatum type 2 strains. PFGE performed with three different endonucleases revealed a unique large restriction fragment (LRF) pattern for M. celatum type 1 strains, whereas the LRF patterns obtained for M. celatum type 2 strains were polymorphic. Moreover, PFGE of nondigested genomic DNA revealed extrachromosomal elements in M. celatum type 2. The type strain of M. celatum type 3 could not be differentiated from M. celatum type 1 strains on the basis of the results of the RFLP analysis, the PFGE analysis, and the PRA of IS1407. In this study we confirmed that M. celatum types 1 and 2 represent distinct genomic clusters and that the molecular markers in M. celatum type 2 exhibit greater polymorphism than the molecular markers in M. celatum type 1.