Abstract
Zebrafish is a natural host of various Mycobacterium species and a surrogate model organism for tuberculosis research. Mycobacterium marinum is evolutionarily one of the closest non-tuberculous species 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 RNA deep sequencing (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 (MBL) 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.
Competing Interest Statement
Authors H.J.J., S.J.R., A.O., S.A.B., M.I.W., C.V.H, P.I.R., N.T-K. and R.P.D were employed by the company ZF-screens B.V. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from ZF-screens B.V. by which several authors were employed. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.
