PCR-based plasmid typing in Enterococcus faecium strains reveals widely distributed pRE25-, pRUM-, pIP501- and pHTbeta-related replicons associated with glycopeptide resistance and stabilizing toxin-antitoxin systems.
A PCR-based typing scheme was applied to identify plasmids in an epidemiologically and geographically diverse strain collection of Enterococcus faecium (n=93). Replicon types of pRE25 (n=56), pRUM (n=41), pIP501 (n=17) and pHTbeta (n=14) were observed in 83% of the strains, while pS86, pCF10, pAM373, pMBB1 or pEF418 were not detected. Furthermore, 61% of the strains contained the axe-txe (n=42) or/and the omega-epsilon-zeta (n=18) plasmid stabilization loci. Sequence analyses divided the omega-epsilon-zeta operon into two distinct phylogenetic groups. The present typing scheme accounted for about 60% of the total number of plasmids detected by S1 nuclease analyses, which revealed zero to seven plasmids (10 kb to >200 kb) per isolate. Interestingly, strains belonging to the clinically important clonal complex 17 (CC17) yielded a significantly higher number of plasmids (3.1) and pRUM replicons (74%) than non-CC17 strains (2.2% and 35%, respectively). A prevalent genetic linkage between the pRUM-replicon type and axe-txe was demonstrated by cohybridization analyses. The vanA resistance determinant was associated with all four replicon types, but we also confirmed the genetic linkage of vanA to unknown transferable replicons. PCR-based replicon typing, linked to the detection of other important plasmid-encoded traits, seems to be a feasible tool for tracing disseminating resistance plasmids stably maintained in various environments.
Rosvoll
Torill C S
TC
Department of Medical Biology, University of Tromsø, Tromsø, Norway.
Pedersen
Torunn
T
Sletvold
Hege
H
Johnsen
Pål J
PJ
Sollid
Johanna E
JE
Simonsen
Gunnar S
GS
Jensen
Lars B
LB
Nielsen
Kaare M
KM
Sundsfjord
Arnfinn
A
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000992:Antitoxins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016984:Enterococcus faecium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D042822:Genomic Instability; D005838:Genotype; D006020:Glycopeptides / Q000494:pharmacology*; D006801:Humans; D017720:Molecular Epidemiology; D010802:Phylogeny; D010957:Plasmids / Q000145:classification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011200:Poultry; D012093:Replicon; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D006020:Glycopeptides; C071437:VanA ligase, Bacteria; D019729:Carbon-Oxygen Ligases