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. 1997 Apr;35(4):969–972. doi: 10.1128/jcm.35.4.969-972.1997

The effect of Tn916 insertions on contour-clamped homogeneous electrophoresis patterns of Enterococcus faecalis.

L A Thal 1, J Silverman 1, S Donabedian 1, M J Zervos 1
PMCID: PMC229712  PMID: 9157164

Abstract

Contour-clamped homogeneous gel electrophoresis has increasingly been used and has generally been considered the method of choice for the delineation of enterococcial strains. It has been suggested that the contour-clamped homogeneous electric field (CHEF) electrophoresis digestion patterns of genomic DNA indicate the relatedness of strains when SmaI patterns differ by six or fewer bands. To evaluate the potential reasons for the diversity of bands among clonally related isolates, we studied plasmid-free Enterococcus faecalis FA2-2 and derivatives with transposon Tn916 (encoding for tetracycline resistance) insertions on the chromosome. We obtained derivatives with seven different Tn916 insertion sites and up to two copies of Tn916 on the chromosome, resulting in differences of one to seven bands by CHEF electrophoresis; eight different patterns were observed. With Tn916 insertions, there was either (i) loss of a band(s) with the generation of a new band(s), (ii) the generation of a new band(s) only, or (iii) the loss of a band(s) with no new visible band(s). These results indicate that strains can have up to seven different SmaI bands by CHEF electrophoresis and still be closely related.

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Selected References

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  1. Chow J. W., Kuritza A., Shlaes D. M., Green M., Sahm D. F., Zervos M. J. Clonal spread of vancomycin-resistant Enterococcus faecium between patients in three hospitals in two states. J Clin Microbiol. 1993 Jun;31(6):1609–1611. doi: 10.1128/jcm.31.6.1609-1611.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Chow J. W., Perri M. B., Thal L. A., Zervos M. J. Mobilization of the penicillinase gene in Enterococcus faecalis. Antimicrob Agents Chemother. 1993 May;37(5):1187–1189. doi: 10.1128/aac.37.5.1187. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Clewell D. B. Plasmids, drug resistance, and gene transfer in the genus Streptococcus. Microbiol Rev. 1981 Sep;45(3):409–436. doi: 10.1128/mr.45.3.409-436.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dembry L. M., Vazquez J. A., Zervos M. J. DNA analysis in the study of the epidemiology of nosocomial candidiasis. Infect Control Hosp Epidemiol. 1994 Jan;15(1):48–53. doi: 10.1086/646817. [DOI] [PubMed] [Google Scholar]
  5. Donabedian S. M., Chow J. W., Boyce J. M., McCabe R. E., Markowitz S. M., Coudron P. E., Kuritza A., Pierson C. L., Zervos M. J. Molecular typing of ampicillin-resistant, non-beta-lactamase-producing Enterococcus faecium isolates from diverse geographic areas. J Clin Microbiol. 1992 Nov;30(11):2757–2761. doi: 10.1128/jcm.30.11.2757-2761.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Forbes B. A., Schaberg D. R. Transfer of resistance plasmids from Staphylococcus epidermidis to Staphylococcus aureus: evidence for conjugative exchange of resistance. J Bacteriol. 1983 Feb;153(2):627–634. doi: 10.1128/jb.153.2.627-634.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Franke A. E., Clewell D. B. Evidence for a chromosome-borne resistance transposon (Tn916) in Streptococcus faecalis that is capable of "conjugal" transfer in the absence of a conjugative plasmid. J Bacteriol. 1981 Jan;145(1):494–502. doi: 10.1128/jb.145.1.494-502.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Gawron-Burke C., Clewell D. B. A transposon in Streptococcus faecalis with fertility properties. Nature. 1982 Nov 18;300(5889):281–284. doi: 10.1038/300281a0. [DOI] [PubMed] [Google Scholar]
  9. Gawron-Burke C., Clewell D. B. Regeneration of insertionally inactivated streptococcal DNA fragments after excision of transposon Tn916 in Escherichia coli: strategy for targeting and cloning of genes from gram-positive bacteria. J Bacteriol. 1984 Jul;159(1):214–221. doi: 10.1128/jb.159.1.214-221.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Goering R. V. Molecular epidemiology of nosocomial infection: analysis of chromosomal restriction fragment patterns by pulsed-field gel electrophoresis. Infect Control Hosp Epidemiol. 1993 Oct;14(10):595–600. doi: 10.1086/646645. [DOI] [PubMed] [Google Scholar]
  11. Hall L. M. Are point mutations or DNA rearrangements responsible for the restriction fragment length polymorphisms that are used to type bacteria? Microbiology. 1994 Jan;140(Pt 1):197–204. doi: 10.1099/13500872-140-1-197. [DOI] [PubMed] [Google Scholar]
  12. Miranda A. G., Singh K. V., Murray B. E. DNA fingerprinting of Enterococcus faecium by pulsed-field gel electrophoresis may be a useful epidemiologic tool. J Clin Microbiol. 1991 Dec;29(12):2752–2757. doi: 10.1128/jcm.29.12.2752-2757.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Murray B. E., Singh K. V., Heath J. D., Sharma B. R., Weinstock G. M. Comparison of genomic DNAs of different enterococcal isolates using restriction endonucleases with infrequent recognition sites. J Clin Microbiol. 1990 Sep;28(9):2059–2063. doi: 10.1128/jcm.28.9.2059-2063.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Patterson J. E., Zervos M. J. High-level gentamicin resistance in Enterococcus: microbiology, genetic basis, and epidemiology. Rev Infect Dis. 1990 Jul-Aug;12(4):644–652. doi: 10.1093/clinids/12.4.644. [DOI] [PubMed] [Google Scholar]
  15. Quintiliani R., Jr, Courvalin P. Conjugal transfer of the vancomycin resistance determinant vanB between enterococci involves the movement of large genetic elements from chromosome to chromosome. FEMS Microbiol Lett. 1994 Jun 15;119(3):359–363. doi: 10.1111/j.1574-6968.1994.tb06913.x. [DOI] [PubMed] [Google Scholar]
  16. Seetulsingh P. S., Tomayko J. F., Coudron P. E., Markowitz S. M., Skinner C., Singh K. V., Murray B. E. Chromosomal DNA restriction endonuclease digestion patterns of beta-lactamase-producing Enterococcus faecalis isolates collected from a single hospital over a 7-year period. J Clin Microbiol. 1996 Aug;34(8):1892–1896. doi: 10.1128/jcm.34.8.1892-1896.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Smith C. L., Cantor C. R. Purification, specific fragmentation, and separation of large DNA molecules. Methods Enzymol. 1987;155:449–467. doi: 10.1016/0076-6879(87)55030-3. [DOI] [PubMed] [Google Scholar]
  18. Tenover F. C., Arbeit R. D., Goering R. V., Mickelsen P. A., Murray B. E., Persing D. H., Swaminathan B. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol. 1995 Sep;33(9):2233–2239. doi: 10.1128/jcm.33.9.2233-2239.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]

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