Mycobacterium abscessus subsp. massiliense expressing bacterioferritin have improved resistance to stressful conditions

Abstract

Aims: The importance of bacterioferritin in the virulence and pathogenicity of the genus Mycobacterium is still unclear. The aim of this study was to analyse if the expression of a recombinant bacterioferritin from M. tuberculosis (Mtb) by Mycma could improve the capacity of this bacillus to resist the host defence mechanisms. Methods and Results: Recombinant Mycma, expressing bacterioferritin (Rv1876) from Mtb, was developed by transformation with pMIP12_Rv1876. To determine bacterioferritin influence on Mycma physiology and virulence, the mycobacteria growth was analysed in vitro and in vivo. It was observed that the expression of bacterioferritin improved the growth rate of recombinant Mycma_BfrA under iron excess and oxidative stress, as compared to the wild type. Furthermore, in the murine model of infection, it was observed that Mycma_BfrA-infected mice had higher bacillary load and a more pronounced lesion in the lungs when compared with the wild type. Conclusion: This study showed that bacterioferritin confers additional resistance to stress conditions, resulting in increased pathogenicity of Mycma during mice infection. Significance and Impact of the Study: This study provides new insights about the importance of bacterioferritin in the virulence and pathogenicity of the Mycobacterium genus.