Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae

Abstract

We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB-lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the 'success' of the infectious process.

Whole metagenome profiles of particulates collected from the International Space Station

“…rRNA methylases have been broadly implicated in virulence phenotypes across many bacterial species, including S. aureus [82], in addition to conferring resistance to aminoglycosides [83]. Expression of bacterial transposases may also broadly impact virulence through regulating gene expression, allowing for inter-bacterial transfer of mobile virulence elements and promoting in vivo adaptation [84]. Detection of the virulence-associated genes described here is highly relevant in the context of confined human habitation within the ISS, as these components will impact the ability of microorganisms such as Pseudomonas and Staphylococcus to effect particularly problematic and difficult-to-treat clinical manifestations in the crew through host cell invasion or other mechanisms.…”

Diversity and Evolution of the Tn 5801-tet (M)-Like Integrative and Conjugative Elements among Enterococcus, Streptococcus, and Staphylococcus

“…Among type B variants, only the mutator family IS256 was consistently detected upstream of orf13 (types B20, B18, and B19), and this stability persisted even when some particular variants (e.g., B20) were disseminated across genera. Some ISs from the IS256 family have been implicated as modulators of gene expression, suggesting that future studies might reveal the role of this IS in the function of type B Tn5801-like elements (50)(51)(52)(53).…”

Transposase-Mediated Excision, Conjugative Transfer, and Diversity of ICE 6013 Elements in Staphylococcus aureus

“…The lack of antimicrobial resistance determinants or other ORFs that may have obvious selective value to an ICE6013 recipient is also notable. This situation is unlike that of S. aureus Tn5801, which is from the Tn916 family and is associated with the tet(M) tetracycline resistance gene (14), and may be more like that of TnGBS, where the factors that drive the successful spread of the element are unclear (15,51). The presence of multiple ICE6013 subfamilies within S. aureus strains that are associated with food animals (e.g., ED98 and S0385) may also indicate both the lack of exclusion mechanisms that prevent the introduction of multiple copies of the element and the possibility that strains infecting food animals act as reservoirs for the element.…”