tIS Cpe8 , an IS 1595 -Family Lincomycin Resistance Element Located on a Conjugative Plasmid in Clostridium perfringens

Abstract

Clostridium perfringens is a normal gastrointestinal organism that is a reservoir for antibiotic resistance genes and can potentially act as a source from which mobile elements and their associated resistance determinants can be transferred to other bacterial pathogens. Lincomycin resistance in C. perfringens is common and is usually encoded by erm genes that confer macrolide-lincosamide-streptogramin B resistance. In this study we identified strains that are lincomycin resistant but erythromycin sensitive and showed that the lincomycin resistance determinant was plasmid borne and could be transferred to other C. perfringens isolates by conjugation. The plasmid, pJIR2774, is the first conjugative C. perfringens R-plasmid to be identified that does not confer tetracycline resistance. Further analysis showed that resistance was encoded by the lnuP gene, which encoded a putative lincosamide nucleotidyltransferase and was located on tISCpe8, a functional transposable genetic element that was a member of the IS1595 family of transposon-like insertion sequences. This element had significant similarity to the mobilizable lincomycin resistance element tISSag10 from Streptococcus agalactiae. Like tISSag10, tISCpe8 carries a functional origin of transfer within the resistance gene, allowing the element to be mobilized by the conjugative transposon Tn916. The similarity of these elements and the finding that they both contain an oriT-like region support the hypothesis that conjugation may result in the movement of DNA modules that are not obviously mobile since they are not linked to conjugation or mobilization functions. This process likely plays a significant role in bacterial adaptation and evolution.

Site‐specific accretion of an integrative conjugative element together with a related genomic island leads to cis mobilization and gene capture

“…IMEs generally encode their own relaxase and frequently few other proteins involved in conjugation such as the coupling protein. However, five IMEs that do not encode any protein involved in their transfer were recently identified (Achard and Leclercq, 2007; Lyras et al ., 2009; Daccord et al ., 2010). These elements, also described as mobile genomic islands (Daccord et al ., 2010), or transferable insertion sequences (Lyras et al ., 2009) carry their own oriT being processed by the relaxase of the mobilizing element.…”

Conjugative and mobilizable genomic islands in bacteria: evolution and diversity

“…As for transfer of all other tested IMEs, the mobilization of a MGI to a recipient is independent of any cotransfer of the helper ICE, the transconjugants harboring the MGI alone (the most frequent), the ICE alone, or the two elements. Even more unusual IMEs from firmicutes, MTnSag1 (Achard & Leclercq, 2007) and its relative tISCpe8 (Lyras et al, 2009), were found to be mobilizable by Tn916. These elements that can be considered as insertion sequences harboring a passenger gene (Siguier et al, 2009) only encode a lincosamide resistance and a DDE transposase, responsible for the formation of a circular extrachromosomal form of the IME and for its insertion (Achard & Leclercq, 2007).…”

“…Another putative IME encoding a serine recombinase, ICE6180-RD.1, seems to be site-specifically integrated in the 3′ end of rumA that encodes a 23S rRNA methyltransferase (Beres & Musser, 2007). Finally, MTnSag1 from S. agalactiae and the related element tISCpe8 from C. perfringens encode a DDE transposase belonging to IS1595 family and have a low specificity of integration (Achard & Leclercq, 2007;Lyras et al, 2009).…”

The Plasmidome of Firmicutes: Impact on the Emergence and the Spread of Resistance to Antimicrobials

“…CpCP plasmids belong to the pCW3 family and are widely spread among isolates of C. perfringens, carrying genes encoding AbR (tetracycline [tetAB(P)], chloramphenicol [catP-Tn4451], lincomycin [lnuP-tISCpe8]) and/or enterotoxins, ε-toxin, or iota-toxin production that determine different toxinotypes (56,(229)(230)(231). All pCW3-like plasmids have a conjugative transfer locus of 11 open reading frames (orfs) (tcp [transfer C. perfringens]) that includes an integrase and a T4CP protein but lacks relaxase (73,231).…”