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Updated: Jun 17, 2026
09:38
Physical Isolation of Endospores from Environmental Samples by Targeted Lysis of Vegetative Cells
Published on: January 21, 2016
Do mycobacteria produce endospores?
Bjorn A Traag1, Adam Driks, Patrick Stragier
1The Biological Laboratories, Harvard University, Cambridge, MA 02138, USA.
Summary
Mycobacterium species, high G+C Gram-positive bacteria, are unlikely to form endospores. Genetic analysis and experimental tests did not support previous findings of endospore formation in M. marinum.
Area of Science:
- Microbiology
- Bacteriology
- Genomics
Background:
- Mycobacterium species are high G+C Gram-positive bacteria.
- A previous study suggested M. marinum and M. bovis bacillus Calmette-Guérin form endospores, previously only observed in low G+C Gram-positive bacteria.
Purpose of the Study:
- To investigate the genetic basis and experimental evidence for endospore formation in Mycobacterium species.
- To re-evaluate the claim of endospore formation in M. marinum.
Main Methods:
- Comparative genomics to identify orthologs of conserved endospore formation genes.
- Light microscopy to detect endospores in M. marinum.
- Heat resistance assays to quantify heat-resistant colony-forming units in M. marinum cultures and infected frogs.
Main Results:
- Mycobacterium genomes lack key conserved genes essential for endospore formation found in low G+C bacteria.
- Endospores were not detected in M. marinum by light microscopy.
- No heat-resistant colony-forming units were found in aged M. marinum cultures or in frogs infected with M. marinum.
Conclusions:
- The genetic machinery for endospore formation appears absent in Mycobacterium species.
- Experimental evidence does not support the presence of endospores in M. marinum.
- It is unlikely that Mycobacterium species are capable of forming endospores.
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