Characterization of aMycobacterium aviumsubsp.aviumOperon Associated with Virulence and Drug Detoxification

Abstract

The lprG-p55 operon of Mycobacterium tuberculosis and Mycobacterium bovis is involved in the transport of toxic compounds. P55 is an efflux pump that provides resistance to several drugs, while LprG is a lipoprotein that modulates the host's immune response against mycobacteria. The knockout mutation of this operon severely reduces the replication of both mycobacterial species during infection in mice and increases susceptibility to toxic compounds. In order to gain insight into the function of LprG in the Mycobacterium avium complex, in this study, we assayed the effect of the deletion of lprG gene in the D4ER strain of Mycobacterium avium subsp. avium. The replacement of lprG gene with a hygromycin cassette caused a polar effect on the expression of p55. Also, a twofold decrease in ethidium bromide susceptibility was observed and the resistance to the antibiotics rifampicin, amikacin, linezolid, and rifabutin was impaired in the mutant strain. In addition, the mutation decreased the virulence of the bacteria in macrophages in vitro and in a mice model in vivo. These findings clearly indicate that functional LprG and P55 are necessary for the correct transport of toxic compounds and for the survival of MAA in vitro and in vivo.

Isolation, Identification, and Characterization of a New Highly Pathogenic Field Isolate of Mycobacterium avium spp. avium

“…Virulence is a reflection of pathogenicity of the bacterial pathogen. The virulence of MAA is affected by various factors and could change with different hosts and environments ( 59 ). The extent of intracellular replication in cell cultures, guinea pigs and mice is widely used as a measure for mycobacterial virulence ( 60 , 61 ).…”

“…The isolated MAA strain here was proven to have strong virulence (Figure 3 ). Compared to intracellular bacterial replication or macrophage infection ( 59 , 63 ), it was more intuitive to use mortality as an indicator of virulence, especially for a bacterial pathogen of strong virulence.…”

Differential Protein Expression in Exponential and Stationary Growth Phases of Mycobacterium avium subsp. hominissuis 104

“…Its implication in mycobacterium virulence has appeared through the induction of mitochondrial fission, interference with complex I and complex II respiration, and modification of mitochondrial calcium uptake, which in turn proposes that LprG-stimulated cells are in a lower bioenergetics state, which could support its immunosuppressive capacity in infection [ 29 ]. The identification of LprG protein in M. tuberculosis was previously confirmed as P27 in the Mycobacterium tuberculosis complex and its gene is conserved across several pathogenic and nonpathogenic Mycobacterium species [ 30 ].…”

Differential Protein Expression in Exponential and Stationary Growth Phases of Mycobacterium avium subsp. hominissuis 104

“…Its implication in mycobacterium virulence has been appeared through the induction of mitochondrial ssion, interference with complex I and complex II respiration, and modi cation of mitochondrial calcium uptake, which in turn proposing that LprG-stimulated cells are in a lower bioenergetics state, which could support its immunosuppressive capacity in infection (36). The identi cation of LprG protein in M. tuberculosis was previously con rmed as P27 in the Mycobacterium tuberculosis complex and its gene is conserved across several pathogenic and nonpathogenic Mycobacterium species (37).…”