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Antimicrobial Agents and Chemotherapy, September 2000, p. 2588-2589, Vol. 44, No. 9
0066-4804/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

LETTERS TO THE EDITOR

Molecular Analysis of Tn1546 in vanA-Containing Enterococcus spp. Isolated from Humans and Poultry

	LETTER

The genes encoding the VanA type of vancomycin resistance in enterococci are located on elements related to Tn1546 (1). Heterogeneity of Tn1546 in Enterococcus faecium has been previously reported (3, 4, 6, 9, 10, 12, 14, 15, 16) and includes deletions, insertions, and mutations. In this study, Tn1546 elements from 43 vanA-containing isolates of different enterococcal species with diverse pulsed-field gel electrophoresis (PFGE) patterns (criteria of Tenover et al. [13]) were analyzed: 30 E. faecium isolates (18 from chicken feces or products and 12 from human fecal samples) showing 25 unrelated PFGE patterns, 7 Enterococcus durans isolates with two unrelated PFGE patterns, (chicken feces or products), 5 Enterococcus hirae isolates (4 from chicken feces or products and 1 from a human fecal sample known to have an indistinguishable or a closely related PFGE pattern), and 1 Enterococcus faecalis isolate (from a chicken product).

PCR products were obtained from all isolates for the seven genes of Tn1546 (vanR, vanS, vanH, vanY [10], vanA [16], vanX [11], and vanZ [8]); IS1216V-related sequences (6) were also demonstrated by PCR for all 43 isolates. When the vanXY (9) region was amplified, the expected 1,947-bp fragment was obtained with 36 of the 43 isolates; however, in all 5 E. hirae isolates and in 2 E. faecium isolates (both from chickens, with different PFGE patterns) the fragment amplified was longer than expected. Results of hybridization of vanXY PCR products with an IS1216V probe indicated that IS1216V was located within the vanXY region in these seven isolates and outside this region in the other isolates. An IS1216V-like sequence was first described within the intergenic vanXY region (5) and later both within and outside Tn1546 (3, 6); disruption of vanS by IS1216V has been found in a clinical E. faecium isolate (2). Despite these reports for E. faecium, this is the first time that IS1216V has been reported within the vanXY region of E. hirae. The restriction of the IS1216V-vanXY association to E. hirae and two E. faecium strains isolated from chickens could suggest interspecies transmission of these transposons in animal gastrointestinal tracts.

IS1251 sequences (6) were detected in 18 E. faecium isolates (13 from chickens and 5 from humans; 15 unrelated PFGE patterns) but not in the other species tested. Analysis of vanSH (9) amplicons and hybridization showed that IS1251 was not included in this region. IS1251 has been previously found in the vanSH intergenic region and at other sites in E. faecium (4, 6).

IS1476, first found in the vanY gene of an E. faecium isolate (9), was not detected in our strains nor in two other studies (6, 15). Recently, a 1-bp difference in vanX was found at position 8234, with either a G (G type) or a T (T type) (6). All our vanA isolates, except one (E. faecium from ground chicken), belonged to the G type as determined by DdeI digestion of the vanX gene PCR fragment (315 bp) (6). The G type has been associated with poultry, and the T type has been associated with porcine E. faecium isolates (3, 7). Both types have been found among isolates from humans in different countries (7), although we found only the G type among vancomycin-resistant enterococci isolated from humans in Spain.

In conclusion, vanA-containing E. faecium, E. faecalis, E. hirae, and E. durans strains of human and animal origins were found to contain similar genetic arrangements of the vanA gene cluster, suggesting either horizontal transfer, the existence of a common reservoir, or a predilection for insertion of certain elements at specific sites.

	FOOTNOTES

^* Phone: 34-941-299284

Fax: 34-941-299274

E-mail: carmen.torres{at}daa.unirioja.es

	REFERENCES

1.	Arthur, M., F. Molinas, F. Depardieu, and P. Courvalin. 1993. Characterization of Tn1546, a Tn3-related transposon conferring glycopeptide resistance by synthesis of depsipeptide peptidoglycan precursors in Enterococcus faecium BM4147. J. Bacteriol. 175:117-127[Abstract/Free Full Text].
2.	da Costa Darini, A. L., M. F. I. Palepou, D. James, and N. Woodford. 1999. Disruption of vanS by IS1216V in a clinical isolate of Enterococcus faecium with vanA glycopeptide resistance. Antimicrob. Agents Chemother. 43:995-996[Free Full Text].
3.	Descheemaeker, P. R. M., S. Chapelle, L. A. Devriese, P. Butaye, P. Vandamme, and H. Goossens. 1999. Comparison of glycopeptide-resistant Enterococcus faecium isolates and glycopeptide resistance genes of human and animal origins. Antimicrob. Agents Chemother. 43:2032-2037[Abstract/Free Full Text].
4.	Handwerger, S., J. Skoble, L. F. Discotto, and M. J. Pucci. 1995. Heterogeneity of the vanA gene cluster in clinical isolates of enterococci from the Northeastern United States. Antimicrob. Agents Chemother. 39:362-368[Abstract/Free Full Text].
5.	Handwerger, S., and J. Skoble. 1995. Identification of chromosomal mobile element conferring high-level vancomycin resistance in Enterococcus faecium. 39:2446-2453.
6.	Jensen, L. B., P. Ahrens, L. Dons, R. N. Jones, A. M. Hammerum, and F. M. Aarestrup. 1998. Molecular analysis of Tn1546 in Enterococcus faecium isolated from animals and humans. J. Clin. Microbiol. 36:437-442[Abstract/Free Full Text].
7.	Jensen, L. B. 1998. Differences in the occurrence of two base pair variants of Tn1546 from vancomycin-resistant enterococci from humans, pigs, and poultry. Antimicrob. Agents Chemother. 42:2463-2464[Free Full Text].
8.	Kirk, M., R. L. R. Hill, M. W. Casewell, and D. Beighton. 1997. Isolation of vancomycin-resistant enterococci from supermarket poultry. Adv. Exp. Med. Biol. 418:289-291[Medline].
9.	Mackinnon, M. G., M. A. Drebot, and G. J. Tyrrell. 1997. Identification and characterization of IS1476, an insertion sequence-like element that disrupts vanY function in a vancomycin-resistant Enterococcus faecium strain. Antimicrob. Agents Chemother. 41:1805-1807[Abstract].
10.	Miele, A., M. Bandera, and B. P. Goldstein. 1995. Use of primers selective for vancomycin resistance genes to determine van genotype in enterococci and to study gene organization in vanA isolates. Antimicrob. Agents Chemother. 39:1772-1778[Abstract].
11.	Reynolds, P. E., F. Depardieu, S. Dutka-Malen, M. Arthur, and P. Courvalin. 1994. Glycopeptide resistance mediated by enterococcal transposon Tn1546 requires production of VanX for hydrolysis of D-alanyl-D-alanine. Mol. Microbiol. 13:1065-1070[CrossRef][Medline].
12.	Stobberingh, E., A. van den Bogaard, N. London, C. Driessen, J. Top, and Rob Willems. 1999. Enterococci with glycopeptide resistance in turkeys, turkey farmers, turkey slaughterers, and (sub)urban residents in the south of The Netherlands: evidence for transmission of vancomycin resistance from animals to humans. Antimicrob. Agents Chemother. 43:2215-2221[Abstract/Free Full Text].
13.	Tenover, F. C., R. D. Arbeit, R. V. Goering, P. A. Mickelsen, B. E. Murray, D. H. Persing, and B. Swaminathan. 1995. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J. Clin. Microbiol. 33:2233-2239[Medline].
14.	van den Braak, N., A. van Belkum, M. Van Keulen, J. Vliegenthart, H. A. Verbrugh, and H. P. Endtz. 1998. Molecular characterization of vancomycin-resistant enterococci from hospitalized patients and poultry products in The Netherlands. J. Clin. Microbiol. 36:1927-1932[Abstract/Free Full Text].
15.	Willems, R. J. L., J. Top, N. van den Braak, A. van Belkum, D. J. Mevius, G. Hendriks, M. van Santen-Verheuvel, and J. D. A. van Embden. 1999. Molecular diversity and evolutionary relationships of Tn1546-like elements in enterococci from humans and animals. Antimicrob. Agents Chemother. 43:483-491[Abstract/Free Full Text].
16.	Woodford, N., D. Morrison, A. P. Johnson, V. Briant, R. C. George, and B. Cookson. 1993. Application of DNA probes for rRNA and vanA genes to investigation of a nosocomial cluster of vancomycin-resistant enterococci. J. Clin. Microbiol. 31:653-658[Abstract/Free Full Text].
17.	Woodford, N., A.-M. A. Adebiyi, M.-F. I. Palepou, and B. D. Cookson. 1998. Diversity of VanA glycopeptide resistance elements in enterococci from humans and nonhuman sources. Antimicrob. Agents Chemother. 42:502-508[Abstract/Free Full Text].

					B. Robredo C. Torres* Área Bioquímica y Biología Molecular Universidad de La Rioja Avenida de la Paz 105 26004 Logroño, Spain
					K. V. Singh B. E. Murray Division of Infectious Diseases Center for the Study of Emerging and Reemerging Pathogens University of Texas Medical School Houston, Texas

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