Transferable vanB2 Tn5382-containing elements in fecal streptococcal strains from veal calves - PubMed (original) (raw)

Transferable vanB2 Tn5382-containing elements in fecal streptococcal strains from veal calves

Kristin H Dahl et al. Antimicrob Agents Chemother. 2003 Aug.

Abstract

Three vancomycin-resistant veal calf fecal streptococci, identified as Streptococcus gallolyticus (n = 2) and Streptococcus lutetiensis, were shown to harbor vanB2 Tn5382-like elements earlier described in enterococci. One S. gallolyticus strain had a 1,495-bp IS256-related element inserted in vanS(B). The vanB2 Tn5382 element present in the plasmid-free S. lutetiensis strain was transferable to Enterococcus faecium BM4105-RF, Enterococcus faecalis JH2-2, and its recombination-deficient derivative, UV202. The transfer frequencies were comparable between recipient strains (from 1 x 10(-7) to 7 x 10(-6)). All transconjugants acquired a vanB-containing chromosomal insert of approximately 100 kb, apparently by site-specific integration. Secondary transconjugants were not observed in intraspecies retransfer experiments. These observations are consistent with a conjugative, selftransmissible, integrative element that might be involved in the interspecies spread of vanB2 resistance determinants. Two JH2-2-derived transconjugants had also gained additional copies of large vanB-containing chromosomal fragments, a process that involves unexplained mechanisms that seems to require functional host cell-dependent recombination mechanisms.

PubMed Disclaimer

Figures

FIG. 1.

FIG. 1.

Restriction fragment analysis of vanB long PCR amplicons. _Bsp_HI/_Dra_I-digested vanB long PCR amplicons were analyzed by agarose gel electrophoresis. Lanes: 1 and 6, 1-kb ladder (Invitrogen Corporation, Carlsbad, Calif.); 2, vanB1 strain V583 with RFLP-1; 3, vanB2 strain 4-G10 with RFLP-2; 4, vanB2 strain 4-C11 with a 1,504-bp insertion in vanSB2 leading to replacement of the 969-bp fragment with restriction fragments of 1,327, 614, and 532 bp (RFLP-2#); 5, vanB2 isolate 5-F9 with RFLP-2. Molecular sizes shown to the left of the gel (in base pairs) refer to the 1-kb ladder.

FIG. 2.

FIG. 2.

Alignment of the terminal portions of the insertion in the vanSB gene of strain 4-C11. The left end following a 12-bp sequence of vanSB (bold) is aligned to the inverted version of the right end. Vertical lines indicate identical nucleotides. A putative imperfect inverted repeat of 25 bp is underlined. The 12-bp sequence of vanSB (bold) immediately in front of the left end is identical to 12 bp at the right end (bold) of the insertion when this sequence is not inverted.

FIG. 3.

FIG. 3.

PFGE of _Sma_I-digested total DNA of the recipients and transconjugants from matings using 5-F9 as donor and JH2-2 and UV202 as recipients (A) and corresponding Southern hybridization with a vanB probe (B). Lanes: 1 and 14, low-range PFG markers (New England Biolabs); 2 to 6, transconjugants obtained after mating with recipient JH2-2; 7, recipient JH2-2; 8, recipient UV202; 9 to 13, transconjugants obtained with UV202 as recipient. JH2-2 and UV202 are isogenic strains and thus have indistinguishable PFGE patterns.

References

    1. Altschul, S. F., W. Gish, W. Miller, E. W. Myers, and D. J. Lipman. 1990. Basic local alignment search tool. J. Mol. Biol. 215**:**403-410. -PubMed
    1. Bickley, J., and R. J. Owen. 1995. Preparation of bacterial genomic DNA. Methods Mol. Biol. 46**:**141-147. -PubMed
    1. Carias, L. L., S. D. Rudin, C. J. Donskey, and L. B. Rice. 1998. Genetic linkage and cotransfer of a novel, vanB_-containing transposon (Tn_5382) and a low-affinity penicillin-binding protein 5 gene in a clinical vancomycin-resistant Enterococcus faecium isolate. J. Bacteriol. 180**:**4426-4434. -PMC -PubMed
    1. Centers for Disease Control. 2002. Staphylococcus aureus resistant to vancomycin—United States 2002. Morb. Mortal. Wkly. Rep. 51**:**565-567. -PubMed
    1. Dahl, K. H., E. W. Lundblad, T. P. Røkenes, Ø. Olsvik, and A. Sundsfjord. 2000. Genetic linkage of the vanB2 gene cluster to Tn_5382_ in vancomycin-resistant enterococci and characterization of two novel insertion sequences. Microbiology 146**:**1469-1479. -PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources