Effect of the deletion of lprG and p55 genes in the K10 strain of Mycobacterium avium subspecies paratuberculosis

• Published in: Research in veterinary science 2021-09, Vol.138, p.1-10
• Main Authors: Viale, Mariana Noelia, Colombatti Olivieri, María Alejandra, Alonso, Natalia, Moyano, Roberto Damián, Imperiale, Belén, Morcillo, Nora, Santangelo, María Paz, Davis, William, Romano, María Isabel
• Format: Article
• Language: English
• Subjects: Animal models; Annotations; Biocompatibility; bMDM; Clarithromycin; Deletion; Drug resistance; Drugs; Efflux; Ethidium bromide; Genes; Immune response; Immunosuppressive agents; Lprg; Macrophages; Mice model; Mutants; Mycobacterium avium; Mycobacterium avium subsp. paratuberculosis mutants; p55; Paratuberculosis; Proteins; Replication; Tuberculosis; Vaccines; Veterinary medicine; Virulence; Virulence factors
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2021.05.019

The lprG-p55 operon of Mycobacterium tuberculosis, M. bovis and M. avium strain D4ER has been identified as a virulence factor involved in the transport of toxic compounds. LprG is a lipoprotein that modulates the host immune response against mycobacteria, whereas P55 is an efflux pump that provides resistance to several drugs. In the present study we search for, and characterize, lprg and p55, putative virulence genes in Mycobacterium avium subsp. paratuberculosis (MAP) to generate a live-attenuated strain of MAP that may be useful in the future as live-attenuated vaccine. For this purpose, we generated and evaluated two mutants of MAP strain K10: one mutant lacking the lprG gene (ΔlprG) and the other lacking both genes lprG and p55 (ΔlprG–p55). None of the mutant strains showed altered susceptibility to first-line and second-line antituberculosis drugs or ethidium bromide, only the double mutant had two-fold increase in clarithromycin susceptibility compared with the wild-type strain. The deletion of lprG and of lprG-p55 reduced the replication of MAP in bovine macrophages; however, only the mutant in lprG-p55 grew faster in liquid media and showed reduced viability in macrophages and in a mouse model. Considering that the deletion of both genes lprG-p55, but not that of lprG alone, showed a reduced replication in vivo, we can speculate that p55 contributes to the survival of MAP in this animal model. •The ∆lprG-p55 mutant had a decreased virulence and elicited high levels of IFNγ.•The lack of lprG and p55 genes decresed only the susceptibility to clarithromicine.•The deletion of the lprG gene alone failed to alter the expression of the p55 gene.•The deletion of the lprG gene alone did not alter the virulence in the mice model.