Partition locus-based classification of selected plasmids in Klebsiella pneumoniae, Escherichia coli and Salmonella enterica spp.: An additional tool

A. Bousquet (1) , S. Henquet (1) , F. Compain (1) , N. Genel (1) , G. Arlet (1, 2, 3, 4) , D. Decré (1, 2)

1 CIMI - Centre d'Immunologie et de Maladies Infectieuses
2 CHU Saint-Antoine [AP-HP]
3 CHU Tenon [AP-HP]
4 CHU Trousseau [APHP]

The dissemination of antimicrobial resistance genes in Enterobacteriaceae has been largely attributed to plasmids, circular DNA molecules capable of autonomous replication. Whereas high-copy-number plasmids primarily rely on passive diffusion for plasmid maintenance, low-copy-number plasmids utilize so-called partition (par) systems. Plasmid partition relies on three structures, i.e. a centromere like DNA site, a centromere-binding protein and an ATPase or a GTPase motor protein for plasmid positioning. Identification and classification of plasmids is essential for tracing plasmids conferring drug resistance. PCR-based replicon typing is currently the standard method for plasmid identification but there are new classification schemes, especially the relaxase gene typing (PRaseT). Here we developed a multiplex PCR set targeting par loci found on the plasmids most frequently encountered in Enterobacteriaceae. This method, called “plasmid partition gene typing” (PAR-T), was validated with 136 transconjugants or transformants harboring various replicon types. The method was tested with 30 multidrug-resistant clinical isolates including Escherichia coli, Klebsiella pneumoniae and Salmonella enterica subsp. enterica carrying 1-4 replicons; all replicons were tested in parallel with PRaseT for comparison. Six multiplex PCRs and one simplex PCR including 18 pairs of primers recognized plasmids of groups IncA/C, FIA, FIB, FIC, FIIk, FII, HI1, HI2, I1, L/M, N, X. Our set of multiplex PCRs showed high specificity for the classification of resistance plasmids except for IncX replicons.

Mots clés: Incompatibility group; Partition system; Plasmid

Domaines: Microbiologie et Parasitologie

A. Bousquet, S. Henquet, F. Compain, N. Genel, G. Arlet, et al.. Partition locus-based classification of selected plasmids in Klebsiella pneumoniae, Escherichia coli and Salmonella enterica spp.: An additional tool. Journal of Microbiological Methods, 2015, 110, pp.85-91. ⟨10.1016/j.mimet.2015.01.019⟩. ⟨hal-01112132⟩