Integration oferm(B)-containing elements through large chromosome fragment exchange inClostridium difficile

Abstract

In Clostridium difficile, erm(B) genes are located on mobile elements like Tn5398 and Tn6215. In previous studies, some of these elements were transferred by conjugation-like mechanisms, mobilized in trans by helper conjugative systems. In this study, we analyzed the genomes of several recipient strains that acquired either Tn5398 or Tn6215-like elements. We demonstrated that the integration of the transposons in the genome of the recipient cell was always due to homologous recombination events, involving exchange of large chromosomal segments. We did not observed transposon transfer to a C. difficile strain in presence of DNAse, suggesting that a possible transformation-like mechanism occurred in this recipient.

Plasmids can transfer to Clostridium difficile CD37 and 630Δerm both by a DNase resistant conjugation-like mechanism and a DNase sensitive mechanism

“…Likewise deletion of oriT reduces plasmid transfer frequencies but does not stop it; low frequency plasmid transfer to CD37 becomes completely sensitive to DNase. A similar DNase sensitive transfer of DNA has been observed when C. difficile donors containing Tn6194 were mixed with a recipient strain (Wasels et al, 2015). In this experiment cell-cell contact was required and free DNA did not result in transfer of Tn6194 (Wasels et al, 2015).…”

“…A similar DNase sensitive transfer of DNA has been observed when C. difficile donors containing Tn6194 were mixed with a recipient strain (Wasels et al, 2015). In this experiment cell-cell contact was required and free DNA did not result in transfer of Tn6194 (Wasels et al, 2015). The role of the oriT in transfer in these experiments was not investigated.…”

Recent advances in the understanding of antibiotic resistance in Clostridium difficile infection

“…The element could integrate into the recipient chromosome either by homologous recombination or by using a site-specific recombinase of the recipient. Another possibility is that a portion of the donor genome containing Tn5398 is transferred to the recipient and integrates by homologous recombination [Wasels et al 2015b Tn6215 is a peculiar element conferring resistance to MLS recently characterized in C. difficile CD80 [Goh et al 2013]. Interestingly, this mobilizable transposon of about 13 kb in length can be transferred between C. difficile strains by a conjugation-like mechanism and by phage ÈC2 transduction.…”

“…Interestingly, this mobilizable transposon of about 13 kb in length can be transferred between C. difficile strains by a conjugation-like mechanism and by phage ÈC2 transduction. Furthermore, very recent data suggest that both Tn6215 and Tn5398 can be transferred to the C. difficile recipient strain C. difficile CD13 by a transformation-like mechanism [Wasels et al 2015b].…”

Clostridioides difficile as a Dynamic Vehicle for the Dissemination of Antimicrobial-Resistance Determinants: Review and In Silico Analysis

“…Tn 6215 is another mobilizable transposon, with a length of 13 kb. It has been found to be transferred among C. difficile strains by a conjugation-like mechanism or by phage ΦC2 transduction [ 29 , 30 ]. Finally, Tn 6189 , described for the first time in 2019, a carrier of erm (B) gene, was found in a collection of both non-toxigenic and toxigenic C. difficile isolates recovered in Southeast Asia, supporting the idea of intraspecies horizontal transfer [ 31 ].…”