ICE SXT vs. ICESh95: Co-existence of Integrative and Conjugative Elements and Competition for a New Host

Abstract

Integrative and conjugative elements (ICEs) are mobile genetic elements that contribute to horizontal gene transfer. The aim of this work was to study different types of ICEs in clinical isolates of the emergent pathogen Shewanella spp., to compare their transfer efficiency and their ability to integrate a new host. Here we show that 3 out of 10 clinical isolates contained an ICE. Two of these elements were similar to ICEs from the SXT/R391 family and the other one was similar to ICE Sh95 , a hybrid platform. Mating assays showed that these elements co-exist for several generations in the same host. Furthermore, transfer rates and competition assays between ICE Sh95 and ICE Sh392 , an SXT-like element, suggest that the latter has evolved into a well-oiled machine that efficiently spread to different bacteria. Our results provide strong evidence of the role that ICEs play in the dissemination of genetic traits in nature and the implications that they have in the global threat of antimicrobial resistance.

Horizontal transfer of large plasmid with type IV secretion system and mosquitocidal genomic island with excision and integration capabilities in Lysinibacillus sphaericus

“…The latter are large DNA segments typically containing recombination and conjugation modules. Integrative mobilizable elements (IMEs) are another recently identified MGE, which differ from ICEs in that they cannot self‐transfer but can be mobilized by ‘co‐resident’ ICEs or conjugative plasmids (Guédon et al ., 2017; Parmeciano et al ., 2019). Both ICEs and IMEs carry genes that can help hosts adapt to specific ecological niches (e.g., antibiotic resistance, pathogenesis, symbiosis, and/or metabolic pathway) (Kohler et al ., 2019; Durrant et al ., 2020; Botelho and Schulenburg, 2021).…”

A Novel Arsenate-Resistant Determinant Associated with ICEpMERPH, a Member of the SXT/R391 Group of Mobile Genetic Elements

“…Mercury operons have also been discovered in ICEVspSpa1 and ICEEniSpa1 from marine aquaculture in Spain and ICEVspPor1 and ICEVspPor3 from Portugal [64], while several Proteus mirabilis isolates from China have also been found to contain mercury resistance determinants [12]. ICESh95 from a Shewanella species and ICEPrSt33672 from Providencia stuartii ATCC33772, both clinical isolates, have also been shown to encode a mercury operon [28,65]. Complete arsenic operons have not been previously identified in SXT/R391 ICE elements but have been detected in several other types of unrelated ICEs.…”