Project description:Zebrafish is a natural host of various Mycobacterium species and a surrogate model organism for tuberculosis research. Mycobacterium marinum (M. marinum) is evolutionarily most closely related to M. tuberculosis and shares the majority of virulence genes. Although zebrafish is not a natural host of the human pathogen, we have previously demonstrated successful robotic infection of zebrafish embryos with M. tuberculosis and performed drug treatment of the infected larvae. In the present study we examined for how long M. tuberculosis can be propagated in zebrafish larvae and tested a time series of infected larvae to study the transcriptional response via Illumina RNAseq. Granuloma-like structures carrying fluorescently labeled M. tuberculosis could be detected up to 9 days post infection. The continued presence of viable M. tuberculosis in the zebrafish larvae was further confirmed using the molecular bacterial load assay. The infected larvae showed a clear and specific transcriptional immune response with a high similarity to the response of zebrafish larvae infected with the surrogate species M. marinum. We conclude that M. tuberculosis can be propagated in zebrafish larvae for at least one week after infection and provide further evidence that M. marinum is a good surrogate model for M. tuberculosis.
