Acquired Antibiotic Resistances in Enterococci

Vivek Kak; Joseph W. Chow

doi:10.1128/9781555817923.ch9

Chapter 9 : Acquired Antibiotic Resistances in Enterococci

VIEW AFFILIATIONS HIDE AFFILIATIONS

Affiliations: 1: Division of Infectious Diseases, B321 Life Sciences Building, Michigan State University, East Lansing, MI 48824; 2: Division of Infectious Diseases (11W), John D. Dingell VA Medical Center and Wayne State University, Detroit, MI 48201-1932

Content Type: Monograph

Publication Year: 2002

Category: Bacterial Pathogenesis

Book DOI: 10.1128/9781555817923

Chapter DOI: 10.1128/9781555817923.ch9

MyBook is a cheap paperback edition of the original book and will be sold at uniform, low price.

Preview this chapter:

Acquired Antibiotic Resistances in Enterococci, Page 1 of 2

< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555817923/9781555812348_Chap09-1.gif /docserver/preview/fulltext/10.1128/9781555817923/9781555812348_Chap09-2.gif

Abstract:

This chapter provides an overview of the most clinically relevant acquired antibiotic resistance mechanisms in enterococci. Enterococci possess a natural, intrinsic resistance to β-lactam antibiotics that is due to the low affinity of their penicillin-binding proteins (PBPs) for the β-lactam agents. Enterococci possess at least five and at times more than nine different PBPs. Enterococci intrinsically possess a low level of resistance to aminoglycosides by limiting transport of the drugs across the cell membrane. The glycopeptide antibiotics vancomycin and teicoplanin are used to treat serious infections due to resistant gram-positive organisms. The most common acquired resistance mechanism among enterococci to the macrolide antibiotics is the production of an enzyme that methylates an adenine residue in the 23S ribosomal RNA of the 50S ribosomal subunit. The high prevalence of multidrug-resistant enterococci in many hospitals has led to an interest in using chloramphenicol as an alternative therapeutic agent. There are two major mechanisms of tetracycline resistance in enterococci: (i) active efflux of the drug across the cell membrane, and (ii) ribosomal protection. The oxazolidinones are a new class of antimicrobial agents developed for use against multidrug-resistant gram-positive bacteria. Evemimicin is an oligosaccharide antimicrobial agent that has shown excellent in vitro activity against enterococci. Ciprofloxacin's activity against enterococci is moderate at best, and quinolone resistance is common among clinical enterococcal isolates.

Citation: Kak V, Chow J. 2002. Acquired Antibiotic Resistances in Enterococci, p 355-383. In Gilmore M, Clewell D, Courvalin P, Dunny G, Murray B, Rice L (ed), The Enterococci. ASM Press, Washington, DC. doi: 10.1128/9781555817923.ch9

Highlighted Text: Show | Hide

Full text loading...

Figures

Acquired Antibiotic Resistances in Enterococci

[com.pub2web.rdf.cci.facet.ContentItem[id=http://asm.metastore.ingenta.com/content/author/10.1128/9781555817923.chap9-1,webId=/content/author/10.1128/9781555817923.chap9-1,properties={foaf_givenname=Vivek, foaf_name=Vivek Kak, foaf_surname=Kak, pub_isAffiliatedWith=[com.pub2web.rdf.cci.facet.ContentItem[id=http://asm.metastore.ingenta.com/content/affiliation/10.1128/9781555817923.chap9-aff1]]}], com.pub2web.rdf.cci.facet.ContentItem[id=http://asm.metastore.ingenta.com/content/author/10.1128/9781555817923.chap9-2,webId=/content/author/10.1128/9781555817923.chap9-2,properties={foaf_givenname=Joseph W., foaf_name=Joseph W. Chow, foaf_surname=Chow, pub_isAffiliatedWith=[com.pub2web.rdf.cci.facet.ContentItem[id=http://asm.metastore.ingenta.com/content/affiliation/10.1128/9781555817923.chap9-aff2]]}]]

/content/10.1128/9781555817923.chap9.fig9-1

Figure 1

Vancomycin resistance operons. Adapted from reference 67 .

10.1128/9781555817923/fig9-1_thmb.gif

10.1128/9781555817923/fig9-1.gif

Figure 1

Vancomycin resistance operons. Adapted from reference 67 .

/content/10.1128/9781555817923.chap9.fig9-2

Figure 2

Induction of VanA/VanB type of resistance. Adapted from reference 14 .

10.1128/9781555817923/fig9-2_thmb.gif

10.1128/9781555817923/fig9-2.gif

Figure 2

Induction of VanA/VanB type of resistance. Adapted from reference 14 .

/content/10.1128/9781555817923.chap9.fig9-3

Figure 3

Biochemical overview of vancomycin resistance. Adapted from reference 67 .

10.1128/9781555817923/fig9-3_thmb.gif

10.1128/9781555817923/fig9-3.gif

Figure 3

Biochemical overview of vancomycin resistance. Adapted from reference 67 .

References

/content/book/10.1128/9781555817923.chap9

1. Aarestrup, F. M.,, F. Bager,, and J. S. Andersen. 2000. The association between the use of avilamycin for growth promotion and the occurrence of resistance among Enterococcus faecium from broilers and pigs. Epidemiological study and changes over time. Microb. Drug Resist. 6: 71– 75.

2. Aarestrup, F. M.,, and L. B. Jensen. 2000. Presence of variations in ribosomal protein L16 corresponding to susceptibility of enterococci to oligosaccharides (avilamycin and evemimicin). Antimicrob. Agents Chemother. 44: 3425– 3427.

3. Allignet, J.,, V. Loncle,, P. Mazodier,, and N. El Solh. 1988. Nucleotide sequence of a staphylococcal plasmid gene, vgb, encoding a hydrolase inactivating the B components of virginiamycin-like antibiotics. Plasmid 20: 271– 275.

4. Allignet, J.,, V. Loncle,, C. Simenel,, M. Delepierre,, and N. El Solh. 1993. Sequence of a staphylococcal gene, vat, encoding an acetyltransferase inactivating the A-type compounds of virginiamycin-like antibiotics. Gene 130: 91– 98.

5. Al-Obeid, S.,, L. Gutmann,, and R. Williamson. 1990. Modification of penicillin-binding proteins of penicillin-resistant mutants of different species of enterococci. J. Antimicrob. Chemother. 26: 613– 618.

6. Arias, C. A., M. Martin-Martinze, T. L. Blundell, M. Arthur, P. Courvalin, and P. E. Reynolds. 1999. Characterization and modeling of VanT: a novel, membrane-bound, serine racemase from vancomycin-resistant Enterococcus gallinarum BM4174. Mol. Microbiol. 31: 1653– 1664.

7. Arthur, M.,, and P. Courvalin. 1993. Genetics and mechanisms of glycopeptide resistance in enterococci. Antimicrob. Agents Chemother. 37: 1563– 1571.

8. Arthur, M.,, F. Depardieu,, L. Cabanie,, P. Reynolds,, and P. Courvalin. 1998. Requirement of the VanY and VanX d,d-peptidases for glycopeptide resistance in enterococci. Mol. Microbiol. 30: 819– 830.

9. Arthur, M.,, F. Depardieu,, and P. Courvalin. 1999. Regulated interactions between partner and non-partner sensors and response regulators that control glycopeptide resistance gene expression in enterococci. Microbiology 145: 1849– 1858.

10. Arthur, M.,, F. Depardieu,, C. Molinas,, P. Reynolds,, and P. Courvalin. 1995. The vanZ gene of Tn l546 from Enterococcus faecium BM4147 confers resistance to teicoplanin. Gene 154: 87– 92.

11.Arthur, M., C. Molinas, T. D. Bugg, G. D. Wright, C. T. Walsh, and P. Courvalin. 1992. Evidence for in vivo incorporation of D-lactate into peptidoglycan precursors of vancomycin-resistant enterococci. Antimicrob. Agents Chemother. 36: 867– 869.

12. Arthur, M.,, C. Molinas,, and P. Courvalin. 1992. The VanS-VanR two component regulatory system controls synthesis of depsipeptide peptidoglycan precursors in Enterococcus faecium BM4147. J. Bacteriol. 174: 2582– 2591.

13. Arthur, M.,, C. Molinas,, F. Depardieu,, and P. Courvalin. 1993. Characterization of Tn l546, a Tn 3-related transposon conferring glycopeptide resistance by synthesis of depsipeptide peptidoglycan precursors in Enterococcus faecium BM4147. J. Bacteriol. 175: 117– 127.

14. Arthur, M.,, and R. Quintiliani, Jr. 2001. Regulation of VanA- and VanB-type glycopeptide resistance in enterococci. Antimicrob. Agents Chemother. 45: 375– 381.

15.Aslangul, E., M. Baptista, B. Fantin, R. Depardieu, M. Arthur, P. Courvalin, and C. Carbon. 1997. Selection of glycopeptide-resistant mutants of VanB-type Enterococcus faecalis BM4281 in vitro and in experimental endocarditis. J. Infect. Dis. 175: 598– 605.

16.Azucena, E., I. Grapsas, and S. Mobashery. 1997. Properties of a bifunctional bacterial antibiotic resistance enzyme that catalyzes ATP-dependent 2"-phosphorylation and acetyl-CoA-dependent 6'-acetylation of aminoglycosides. J. Am. Chem. Soc. 119: 2317– 2318.

17. Baptista, M.,, F. Depardieu,, P. Reynolds,, P. Courvalin,, and M. Arthur. 1997. Mutations leading to increased levels of resistance to glycopeptide antibiotics in VanB-type enterococci. Mol. Microbiol. 25: 93– 105.

18. Baptista, M.,, P. Rodrigues,, F. Depardieu,, P. Courvalin,, and M. Arthur. 1999. Single-cell analysis of glycopeptide resistance gene expression in teicoplanin-resistant mutants of a VanB-type Enterococcus faecalis. Mol. Microbiol. 32: 17– 28.

19. Belova, L.,, T. Tenson,, L. Xiong,, P. M. McNicholas,, and A. S. Mankin. 2001. A novel site of antibiotic action in the ribosome: interaction of evernimicin with the large ribosomal subunit. Proc. Natl. Acad. Set. USA 98: 3726– 3731.

20. Bentorcha, F.,, G. de Cespadfes,, and T. Horaud. 1991. Tetracycline resistance heterogeneity in Enterococcus faecium. Antimicrob. Agents Chemother. 35: 808– 812.

21. Billot-Klein, D.,, D. Blanot,, L. Gutmann,, and J. van Heijenoort. 1994. Association constants for the binding of vancomycin and teicoplanin to N-acetyl-D-alanyl-D-alanine and N-acetyl-D-alanyl-D-serine. Biochem. J. 304: 1021– 1022.

22. Billot-Klein, D.,, L. Gutmann,, S. Sable,, E. Guittet,, and J. van Heijenoort. 1994. Modification of peptidoglycan precursors is a common feature of the low-level vancomycin-resistant VANB-type enterococcus D366 and of the naturally glycopeptide-resistant species Lactobacillus casei, Pediococcus pentosaceus, Leuconostoc mesenteroides, and Enterococcus gallinarum. J. Bacteriol. 176: 2398– 2405.

23. Bonten, M. J. M., M. K. Hayden, C. Nathan, J. van Voorhis, M. Matushek, S. Slaughter, T. Rice, and R. A. Weinstein. 1996. The epidemiology of colonisation of patients and environment with vancomycin-resistant enterococci. Lancet 348: 1615– 1619.

24. Bozdogan, B.,, L. Berrezouga,, M.-S. Kuo,, D. A. Yurek,, K. A. Farley,, B. J. Stockman,, and R. Leclercq. 1999. A new resistance gene, linB, conferring resistance to lincosamides by nucleotidylation in Enterococcus faecium HM1025. Antimicrob. Agents Chemother. 43: 925– 929.

25. Bozdogan, B.,, and R. Leclercq. 1999. Effects of genes encoding resistance to streptogramins A and B on the activity of qumupristin-dalfopristin against Enterococcus faecium. Antimicrob. Agents Chemother. 43: 2720– 2725.

26. Bozdogan, B.,, R. Leclercq,, A. Lozniewski,, and M. Weber. 1999. Plasmidmediated coresistance to streptogramins and vancomycin in Enterococcus faecium HM1032. Antimicrob. Agents Chemother. 43: 2097– 2098.

27. Brisson-Noel, A.,, S. Dutka-Malen,, C. Molinas,, R. Leclercq,, and P. Courvalin. 1990. Cloning and heterospecific expression of the resistance determinant vanA encoding high-level resistance to glycopeptides in Enterococcus faecium BM4147. Antimicrob. Agents Chemother. 34: 924– 927.

28. Bugg, T. D.,, G. D. Wright,, S. Dutka-Malen,, M. Arthur,, P. Courvalin,, and C. T. Walsh. 1991. Molecular basis for vancomycin resistance in Enterococcus faecium BM4147: biosynthesis of a depsipeptide peptidoglycan precursor by vancomycin resistance proteins VanH and VanA. Biochemistry 30: 10408– 10415.

29.Buu-Hoï, A., C. Le Bouguenec, and T. Horaud. 1990. High-level chromosomal gentamicin resistance in Streptococcus agalactiae (group B). Antimicrob. Agents Chemother. 34: 985– 988.

30. Caillaud, R., R Trieu-Cuot, C. Carlier, and R Courvalin. 1987. Nucleotide sequence of the kanamycin resistance determinant of the pneumococcal transposon Tn 1545: evolutionary relationships and transcriptional analysis of aphA-3 genes. Mol. Gen. Genet. 207: 509– 513.

31. Calderwood, S. B.,, C. Wennersten,, and R. C. Moellering, Jr. 1981. Resistance to antibiotic synergism in Streptococcus faecalis: further studies with amikacin and with a new amikacin derivative, 4'-deoxy-6'- N-methylamikacin. Antimicrob. Agents. Chemother. 19: 549– 555.

32. Carias, L. L.,, S. D. Rudin,, C. J. Donskey,, and L. B. Rice. 1998. Genetic linkage and co-transfer 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.

33.Carlier, C, and R Courvalin. 1990. Emergence of 4', 4"-aminoglycoside nucleotidyltransferase in enterococci. Antimicrob. Agents Chemother. 34: 1565– 1569.

34. Casadewall, B., and R Courvalin. 1999. Characterization of the vanD glycopeptide resistance gene cluster from Enterococcus faecium BM4339. J. Bacteriol. 181: 3644– 3648.

35.Cercenado, E., M. F. Vicente, M. D. Diaz, C. Sanchez-Carrillo, and M. Sanchez-Rubiales. 1996. Characterization of clinical isolates of β-lactamase-negative, highly ampicillin-resistant Enterococcus faecalis. Antimicrob. Agents Chemother. 40: 2420– 2422.

36. Charpentier, E.,, G. Gerbaud, and R Courvalin. 1994. Presence of the Listeria tetracycline resistance gene tet(S) in Enterococcus faecalis. Antimicrob. Agents Chemother. 38: 2330– 2335.

37. Chow, J. W. 2000. Aminoglycoside resistance in enterococci. Clin. Infect. Dis. 31: 586– 589.

37a. Chow, J. W. Unpublished data.

38. Chow, J. W.,, S. M. Donabedian,, and M. J. Zervos. 1997. Emergence of increased resistance to quinupristin/dalfopristin during therapy for Enterococcus faecium bacteremia. Clin. Infect. Dis. 24: 90– 91.

38a. Chow, J. W.,, V. Kak,, I. You,, S. J. Kao,, J. Petrin,, D. B. Clewell,, S. A. Lerner,, G. H. Miller,, and K. J. Shaw. 2001. Aminoglycoside resistance genes aph(2″)Ib and aac(6′)Im detected together in strains of both Escherichia coli and Enterococcus faecium. Antimicrob. Agents Chemother. 45: 2691– 2694.

39. Chow, J. W.,, M. J. Zervos,, S. A. Lerner,, L. A. Thai,, S. M. Donabedian,, D. D. Jaworski,, S. Tsai,, K. J. Shaw,, and D. B. Clewell. 1997. A novel gentamicin resistance gene in Enterococcus. Antimicrob. Agents Chemother. 41: 511– 514.

40. Clancy, J.,, J. Petitpas,, R. Dib-Hajj,, W. Yuan,, M. Cronan, A. V. Kamath, J. Bergeron, and J. A. Retsema. 1996. Molecular cloning and functional analysis of a novel macrolide-resistance determinant, mefA, from Streptococcus pyogenes. Mol. Microbiol. 22: 867– 879.

41. Clark, N. C, O. Olsvik, J. M. Swenson, C. A. Spiegel, and F. C. Tenover. 1999. Detection of a streptomycin/spectinomycin adenylyltransferase gene ( aadA) in Enterococcus faecalis. Antimicrob. Agents Chemother. 43: 157– 160.

42. Clark, N. C, L. M. Teixeira, R. R. Facklam, and F. C. Tenover. 1998. Detection and differentiation of vanC-1, vanC-2 and vanC-3 glycopeptide resistance genes in enterococci. J. Clin. Microbiol. 36: 2294– 2297.

43. Collate, E.,, C. Carlier, and R Courvalin. 1983. The chromosomal 3',5 ,,-amino-glycoside phosphotransferase in Streptococcus pneumoniae is closely related to its plasmid-coded homologs in Streptococcus faecalis and Staphylococcus aureus. J. Bacteriol. 156: 1373– 1377.

44. Costa, Y.,, M. Galimand,, R. Leclercq,, J. Duval,, and P. Courvalin. 1993. Characterization of the chromosomal aac(6′)-Ii gene specific for Enterococcus faecium. Antimicrob. Agents Chemother. 37: 1896– 1903.

45. del Campo, R.,, C. Tenorio,, C. Rubio,, J. Castillo,, C. Torres,, and R. Gomez-Lus. 2000. Aminoglycoside-modifying enzymes in high-level streptomycin and gentamicin resistant Enterococcus spp. in Spain. Int. J. Antimicrob. Agents 15: 221– 226.

46.Derbise, A., S. Aubert, and N. El Solh. 1997. Mapping the regions carrying the three contiguous antibiotic resistance genes aadE, sat4, and aphA-3 in the genomes of staphylococci. Antimicrob. Agents Chemother. 41: 1024– 1032.

47. Dever, L. L.,, S. M. Smith,, S. Handwerger,, and R. H. Eng. 1995. Vancomycin-dependent Enterococcus faecium isolated from stool following oral vancomycin therapy. J. Clin. Microbiol. 33: 2770– 2773.

48. Dutka-Malen, S.,, C. Molinas,, M. Arthur,, and P. Courvalin. 1992. Sequence of the vanC gene of Enterococcus gallinarum BM4174 encoding a D-alanine:D-alanine ligase-related protein necessary for vancomycin resistance. Gene 112: 53– 58.

49.Edmond, M. B., J. F. Ober, D. L. Weinbaum, M. A. Pfaller, T. Hwang, M. D. Sanford, and R. P. Wenzel. 1995. Vancomycin-resistant Enterococcus faecium bacteremia: risk factors for infection. Clin. Infect. Dis. 20: 1126– 1133.

50. El Amin, N.,, S. Jalal,, and B. Wretlind. 1999. Alterations in GyrA and ParC associated with fluoroquinolone resistance in Enterococcus faecium. Antimicrob. Agents Chemother. 43: 947– 949.

51. Eliopoulos, G. M., B. F. Farber, B. E. Murray, C. Wennersten, and R. C. Moellering, Jr. 1984. Ribosomal resistance of clinical enterococcal isolates to streptomycin. Antimicrob. Agents Chemother. 25: 398– 399.

52. Elisha, B. G.,, and P. Courvalin. 1995. Analysis of genes encoding D-alanine-D-alanine ligase-related enzymes in Leuconostoc mesenteroides and Lactobacillus spp. Gene 152: 79– 83.

53. Evers, S.,, and P. Courvalin. 1996. Regulation of the VanB-type resistance gene expression by the VanS B-VanR B two-component regulatory system in Enterococcus faecalis V583. J. Bacteriol 178: 1302– 1309.

54. Evers, S.,, P. E. Reynolds,, and P. Courvalin. 1994. Sequence of the vanB and ddl genes encoding D-alanine:D-lactate and D-alanine:D-alanine ligases in vancomycin-resistant Enterococcus faecalis V583. Gene 140: 97– 102.

55. Evers, S.,, D. F. Sahm,, and P. Courvalin. 1993. The vanB gene of vancomycin-resistant Enterococcus faecalis V583 is structurally related to genes encoding d-Ala:d-Ala ligases and glycopeptide-resistance proteins VanA and VanC. Gene 124: 143– 144.

56.Farrag, N., I. Eltringham, and H. Liddy. 1996. Vancomycin-dependent Enterococcus faecalis. Lancet 348: 1581– 1582.

57. Ferretti, J. J.,, K. S. Gilmore,, and P. Courvalin. 1986. Nucleotide sequence analysis of the gene specifying the bifunctional 6'-aminoglycoside acetyltransferase 2"-aminoglycoside phosphotransferase enzyme in Streptococcus faecalis and identification and cloning of gene regions specifying the two activities. J. Bacteriol 167: 631– 638.

58. Fines, M.,, B. Perichon,, P. Reynolds,, D. F. Sahm,, and P. Courvalin. 1999. VanE, a new type of acquired glycopeptide resistance in Enterococcus faecalis BM4405. Antimicrob. Agents Chemother. 43: 2161– 2164.

59. Fontana, R.,, M. Aldegheri,, M. Ligozzi,, H. Lopez,, A. Sucari,, and G. Satta. 1994. Overproduction of a low-affinity penicillin-binding protein and high-level ampicillin resistance in Enterococcus faecium. Antimicrob. Agents Chemother. 38: 1980– 1983.

60. Fontana, R.,, R. Cerini,, P. Longoni,, A. Grossato,, and P. Canepari. 1983. Identification of a streptococcal penicillin binding protein that reacts very slowly with penicillin. J. Bacteriol. 155: 1343– 1350.

61. Fontana, R.,, A. Grossato,, L. Rossi,, Y. R. Cheng,, and G. Satta. 1985. Transition from resistance to hypersusceptibility to β-lactam antibiotics associated with loss of a low-affinity penicillin-binding protein in a Streptococcus faecium mutant highly resistant to penicillin. Antimicrob. Agents Chemother. 28: 678– 683.

62. Fontana, R.,, M. Ligozzi,, F. Pittaluga,, and G. Satta. 1996. Intrinsic penicillin resistance in enterococci. Microb. Drug Resist. 2: 209– 213.

63. Fraimow, H.,, and C. Knob. 1997. Amplification of macrolide efflux pumps msr and mef from Enterococcus faecium by polymerase chain reaction, abstr. A-125, p. 22. In Abstracts of the 98th General Meeting of the American Society for Microbiology. American Society for Microbiology, Washington, D.C.

64. Fraimow, H. S.,, D. L. Jungkind,, D. W. Lander,, D. R. Delso,, and J. L. Dean. 1994. Urinary tract infection with an Enterococcus faecalis isolate that requires vancomycin for growth. Ann. Intern. Med. 121: 22– 26.

65. Fridkin, S. K.,, and R. P. Gaynes. 1999. Antimicrobial resistance in intensive care units. Clin. Chest Med. 20: 303– 316.

66.Galimand, M., T. Lambert, G. Gerbaud, and P. Courvalin. 1999. High-level aminoglycoside resistance in the beta-hemolytic group G Streptococcus isolate BM2721. Antimicrob. Agents Chemother. 43: 3008– 3010.

67. Gholizadeh, Y.,, and P. Courvalin. 2000. Acquired and intrinsic glycopeptide resistance in enterococci. Int. J. Antimicrob. Agents. 16: S11– S17.

68. Gonzales, R. D.,, P. C. Schreckenberger,M. B. Graham, S. Kelkar, K. Den-Besten, and J. P. Quinn. 2001. Infections due to vancomycin-resistant Enterococcus faecium resistant to linezolid. Lancet 357: 1179.

69. Gordon, S.,, J. M. Swenson,, B. C. Hill, N. E. Pigott, R. R Facklam, R. C. Cook-sey, C. Thornsberry, Enterococcal Study Group, W. R. Jarvis, and F. C. Tenover. 1992. Antimicrobial susceptibility patterns of common and unusual species of enterococci causing infections in the United States. J. Clin. Microbiol. 30: 2373– 2378.

70. Gray, G. S.,, and W. M. Fitch. 1983. Evolution of antibiotic resistance genes: the DNA sequence of a kanamycin resistance gene from Staphylococcus aureus. Mol. Biol. Evol. 1: 57– 66.

71. Green, M.,, J. H. Shlaes,, K. Barbadora,, and D. M. Shlaes. 1995. Bacteremia due to vancomycin-dependant Enterococcus faecium. Clin. Infect. Dis. 20: 712– 714.

72. Haroche, J.,, J. Allignet,, S. Aubert,, A. E. van den Bogaard,, and N. El Solh. 2000. satG, conferring resistance to streptogramin A, is widely distributed in Enterococcus faecium strains but not in staphylococci. Antimicrob. Agents Chemother. 44: 190– 191.

73.Hayden, M. K. 2000. Insights into the epidemiology and control of infection with vancomycin-resistant enterococci. Clin. Infect. Dis. 31: 1058– 1065.

74. Hayden, M. K.,, G. M. Trenholme,, J. E. Schultz,, and D. R Sahm. 1993. In vivo development of teicoplanin resistance in a VanB Enterococcus faecium. J. Infect. Dis. 167: 1224– 1227.

75. Hodges, T. L.,, S. Zighelboim-Daum,, G. M. Eliopoulos,, C. Wennersten,, and R. C. Moellering, Jr. 1992. Antimicrobial susceptibility changes in Enterococcus faecalis following various penicillin exposure regimens. Antimicrob. Agents Chemother. 36: 121– 125.

76. Hollingshead, S.,, and D. Vapnek. 1985. Nucleotide sequence analysis of a gene encoding a streptomycin/spectinomycin adenylyltransferase. Plasmid 13: 17– 30.

77. Hon, W.-C, G. A. McKay, R R. Thompson, R. M. Sweet, D. S. C. Yang, G. D. Wright, and A. M. Berghuis. 1997. Structure of an enzyme required for aminoglycoside antibiotic resistance reveals homology to eukaryotic protein kinases. Cell 89: 887– 895.

78. Hooper, D. C., 2000. Mechanisms of fluoroquinolone resistance, p. 685– 693. In V. A. Fischetti,, R. P. Novick,, J. J. Ferretti,, D. A. Portnoy,, and J. I. Rood (ed.), Gram-Positive Pathogens. ASM Press, Washington, D.C.

79. Jensen, L. B., N. Frimodt-Meller, and F. M. Aarestrup. 1999. Presence of erm gene classes in gram-positive bacteria of animal and human origin in Denmark. FEMS Microbiol. Lett. 170: 151– 158.

80. Jones, R. N., M. L. Beach, M. A. Pfaller, and G. V. Doern. 1998. Antimicrobial activity of gatifloxacin tested against 1676 strains of ciprofloxacin-resistant gram-positive cocci isolated from patient infections in North and South America. Diagn. Microbiol. Infect. Dis. 32: 247– 252.

81. Jones, R. N.,, R. S. Hare,, F. J. Sabatelli, and the Ziracin Susceptibility Testing Group. 2001. In vitro gram-positive antimicrobial activity of evernimicin (SCH 27899), a novel oligosaccharide, compared with other antimicrobials: a multicentre international trial. J. Antimicrob Chemother. 47: 15– 25.

82.Kanematsu, E., T. Deguchi, M. Yasuda, T. Kawamura, Y. Nishino, and Y. Kawada. 1998. Alterations in the GyrA subunit of DNA gyrase and the ParC subunit of DNA topoisomerase IV associated with quinolone resistance in Enterococcus faecalis. Antimicrob. Agents Chemother. 42: 433– 435.

83. Kao, S. J.,, I. You,, D. B. Clewell,, S. M. Donabedian,, M. J. Zervos,, J. Petrin,, K. J. Shaw,, and J. W. Chow. 2000. Detection of the high-level aminoglycoside resistance gene aph(2")-Ib in Enterococcus faecium. Antimicrob. Agents Chemother. 44: 2876– 2879.

84. Kato, J.,, Y. Nishimura,, R. Imamura,, H. Niki,, S. Hiraga,, and H. Suzuki. 1990. New topoisomerase essential for chromosome segregation in E. coli. Cell 63: 393– 404.

85.Kaufhold, A., and E. Potgieter. 1993. Chromosomally mediated high-level gentamicin resistance in Streptococcus mitis. Antimicrob. Agents Chemother. 37: 2740– 2742.

86. Kloss, P.,, L. Xiong,, D. L. Shinabarger,, and A. S. Mankin. 1999. Resistance mutations in 23S rRNA identify the site of action of the protein synthesis inhibitor linezolid in the ribosomal peptidyltransferase center. J. Mol. Biol. 294: 93– 101.

87. Korten, V.,, W. M. Huang,, and B. E. Murray. 1994. Analysis by PCR and direct DNA sequencing of gyrA mutations associated with fluoroquinolone resistance in Enterococcus faecalis. Antimicrob. Agents Chemother. 38: 2091– 2094.

88. Kotra, L. P.,, J. Haddad,, and S. Mobashery. 2000. Aminoglycosides: perspectives on mechanisms of action and resistance and strategies to counter resistance. Antimicrob. Agents Chemother. 44: 3249– 3256.

89. Krogstad, D. J.,, T. R. Korfhagen,, R. C. Moellering, Jr., C. Wennersten, and M. N. Swartz. 1978. Aminoglycoside-inactivating enzymes in clinical isolates of Streptococcus faecalis: an explanation for resistance to antibiotic synergism. J. Clin. Invest. 62: 480– 486.

90. LeBlanc, D. J.,, L. N. Lee,, and J. M. Inamine. 1991. Cloning and nucleotide base sequence analysis of a spectinomycin adenyltransferase AAD(9) determinant from Enterococcus faecalis. Antimicrob. Agents Chemother. 35: 1804– 1810.

91. Leclercq, R., E. Derlot, J. Duval, and R Courvalin. 1988. Plasmid-mediated resistance to vancomycin and teicoplanin in Enterococcus faecium. N. Engl. J. Med. 319: 157– 161.

92. Leclercq, R.,, S. Dutka-Malen,, A. Brisson-Noel,, C. Molinas,, E. Derlot,, M. Arthur,, J. Duval,, and P. Courvalin. 1992. Resistance of enterococci to aminoglycosides and glycopeptides. Clin. Infect. Dis. 15: 495– 501.

93. Leclercq, R.,, S. Dutka-Malen,, J. Duval,, and P. Courvalin. 1992. Vancomycin resistance gene vanC is specific to Enterococcus gallinarum. Antimicrob. Agents Chemother. 36: 2005– 2008.

94.Ligozzi, M., M. Aldegheri, S. C. Predari, and R. Fontana. 1991. Detection of penicillin-binding proteins immunologically related to penicillin-binding protein 5 Enterococcus hirae ATCC 9790 in Enterococcus faecium and Enterococcus faecalis. FEMS Microbiol. Lett. 83: 335– 340.

95. Ligozzi, M.,, F. Pittaluga,, and R. Fontana. 1993. Identification of a genetic element ( psr) which negatively controls expression of Enterococcus hirae penicillin-binding protein 5. J. Bacteriol. 175: 2046– 2051.

96.Ligozzi, M., F. Pittaluga, and R. Fontana. 1996. Modification of penicillin-binding protein 5 associated with high-level ampicillin resistance in Enterococcus faecium. Antimicrob. Agents Chemother. 40: 354– 357.

97. Lin, A. H.,, R. W. Murray,, T. J. Vidmar,, and K. R. Marotti. 1997. The oxazolidinone eperezolid binds to the 50S ribosomal subunit and competes with binding of chloramphenicol and lincomycin. Antimicrob. Agents Chemother. 41: 2127– 2131.

98. Luna, V. A., P. Coates, E. A. Eady, J. H. Cove, T. T. H. Nguyen, and M. C. Roberts. 1999. A variety of gram-positive bacteria carry mobile mef genes. J. Antimicrob. Chemother. 44: 19– 25.

99.Lynch, C, P. Courvalin, and H. Nikaido. 1997. Active efflux of antimicrobial agents in wild-type strains of enterococci. Antimicrob. Agents Chemother. 41: 869– 871.

100. Mainardi, J.-L.,, R. Legrand,, M. Arthur,, B. Schoot,, J. van Heijenoort,, and L. Gutmann. 2000. Novel mechanism of (-lactam resistance due to bypass of DD-transpeptidation in Enterococcus faecium. J. Biol. Chem. 275: 16490– 16496.

101. Marshall, C. G.,, G. Broadhead, B. K. Leskiw, and G. D. Wright. 1997. D-Ala: D-Ala ligases from glycopeptide antibiotic-producing organisms are highly homologous to the enterococcal vancomycin-resistance ligases VanA and VanB. Proc. Natl. Acad. Sci. USA 94: 6480– 6483.

102. Marshall, C. G.,, I. A. D. Lessard,, I.-S. Park,, and G. D. Wright 1998. Glycopeptide antibiotic resistance genes in glycopeptide-producing organisms. Antimicrob. Agents Chemother. 42: 2215– 2220.

103.Matsumura, M., Y. Katakura, T. Imanaka, and S. Aiba. 1984. Enzymatic and nucleotide sequence studies of a kanamycin-inactivating enzyme encoded by a plasmid from thermophilic bacilli in comparison with that encoded by plasmid pUB110. J. Bacteriol. 160: 413– 420.

104. McKay, G. A., J. Roestamadji, S. Mobashery, and G. D. Wright 1996. Recognition of aminoglycoside antibiotics by enterococcal-staphylococcal aminoglycoside 3'-phosphotransferase type IIIa: role of substrate amino groups. Antimicrob. Agents Chemother. 40: 2648– 2650.

105. McKay, G. A., P. R. Thompson, and G. D. Wright. 1994. Broad spectrum aminoglycoside phosphotransferase type III from Enterococcus: overexpression, purification, and substrate specificity. Biochemistry 33: 6936– 6944.

106. McKessar, S. J.,, A. M. Berry,, J. M. Bell,, J. D. Turnidge,, and J. C. Paton. 2000. Genetic characterization of vanG, a novel resistance locus of Enterococcus faecalis. Antimicrob. Agents Chemother. 44: 3224– 3228.

107. McMurry, L. M.,, and S. B. Levy,. 2000. Tetracycline resistance in gram-positive bacteria, p. 660– 677. In V. A. Fischetti,, R. P. Novick,, J. J. Ferretti,, D. A. Portnoy,, and J. I. Rood (ed.), Gram-Positive Pathogens. ASM Press, Washington, D.C.

108. Mingeot-Leclercq, M.-R, Y. Glupczynski, and P. M. Tulkens. 1999. Aminoglycosides: activity and resistance. Antimicrob. Agents Chemother. 43: 727– 737.

109. Moellering, R. C, Jr., P. K. Linden, J. Reinhardt, E. A. Blumberg, F. Bompart, and G. H. Talbot. 1999. The efficacy and safety of quinupristin/dalfopristin for the treatment of infections caused by vancomycin-resistant Enterococcus faecium. J. Antimicrob. Chemother. 44: 251– 261.

110. Moellering, R. C, Jr., and A. N. Weinberg. 1971. Studies on antibiotic synergism against enterococci. II. Effect of various antibiotics on the uptake of 14C-labelled streptomycin by enterococci. J. Clin. Invest. 50: 2580– 2584.

111. Murphy, E. 1985. Nucleotide sequence of ermA, a macrolide-lincosamide-streptogramin B determinant in Staphylococcus aureus. J. Bacteriol. 162: 633– 640.

112.Murray, B. E. 1992. β-lactamase-producing enterococci. Antimicrob. Agents Chemother. 36: 2355– 2359.

113. Murray, I. A., 2000. Chloramphenicol resistance, p. 678– 684. In V. A. Fischetti,, R. P. Novick,, J. J. Ferretti,, D. A. Portnoy,, and J. I. Rood (ed.), Gram-Positive Pathogens. ASM Press, Washington, D.C.

114. Nakanishi, N.,, S. Yoshida,, H. Wakebe,, M. Inoue,, and S. Mitsuhashi. 1991. Mechanisms of clinical resistance to fluoroquinolones in Enterococcus faecalis. Antimicrob. Agents Chemother. 35: 1053– 1059.

115. Navarro, F.,, and P. Courvalin. 1994. Analysis of genes encoding D-alanine-D-alanine ligase-related enzymes in Enterococcus casseliflavus and Enterococcus flavescens. Antimicrob. Agents Chemother. 38: 1788– 1793.

116. Ounissi, H.,, and P. Courvalin,. 1987. Appendix B: nucleotide sequences of streptococcal genes, p. 275. In J. J. Ferretti,, and R. Curtiss III (ed.), Streptococcal Genetics. American Society for Microbiology, Washington, D.C.

117. Patel, R. 1999. Enterococcal-type glycopeptide resistance genes in non-enterococcal organisms. FEMS Microbiol. Lett. 185: 1– 7.

118. Patel, R.,, K. Piper,, F. R. Cockerill III,, J. M. Steckelberg,, and A. A. Yousten. 2000. The biopesticide Paenibacillus poptlliae has a vancomycin resistance gene cluster homologous to the enterococcal VanA vancomycin resistance gene cluster. Antimicrob. Agents Chemother. 44: 705– 709.

119.Pepper, K., T. Horaud, C. Le Bouguenec, and G. de Cespedes. 1987. Location of antibiotic resistance markers in clinical isolates of Enterococcus faecalis with similar antibiotypes. Antimicrob. Agents Chemother. 31: 1394– 1402.

120. Pepper, K.,, C. Le Bouguenec,, G. de Cespedes,, and T. Horaud. 1986. Dispersal of a plasmid-borne chloramphenicol resistance gene in streptococcal and enterococcal plasmids. Plasmid 16: 195– 203.

121.Perichon, B., B. Casadewall, P. Reynolds, and P. Courvalin. 2000. Glycopeptide-resistant Enterococcus faecium BM4416 is a VanD-type strain with an impaired D-alanine:D-alanine ligase. Antimicrob. Agents Chemother. 44: 1346– 1348.

122. Perichon, B.,, P. Reynolds,, and P. Courvalin. 1997. VanD-type glycopeptide resistant Enterococcus faecium BM4339. Antimicrob. Agents Chemother. 41: 2016– 2018.

123. Petersen, P. J., N. V. Jacobus, W. J. Weiss, P. E. Sum, and R. T. Testa. 1999. In vitro and in vivo antibacterial activities of a novel glycylcycline, the 9- t-butyl-glycylamido derivative of minocycline (GAR-936). Antimicrob. Agents Chemother. 43: 738– 744.

124.Platteeuw, C, F. Michiels, H. Joos, J. Seurinck, and W. M. de Vos. 1995. Characterization and heterologous expression of the tet(L) gene and identification of iso-ISSl elements from Enterococcus faecalis plasmid pJHl. Gene 160: 89– 93.

125. Portillo, A. F. Ruiz-Larrea, M. Zarazaga, A. Alonso, J. Luis Martinez, and C. Torres. 2000. Macrolide resistance genes in Enterococcus spp. Antimicrob. Agents Chemother. 44: 967– 971.

126. Quintiliani, R., Jr., and P. Courvalin. 1994. Conjugal transfer of the vancomycin resistance determinant vanB between enterococci involves the movement of large genetic elements from chromosome to chromosome. FEMS Microbiol. Lett. 119: 359– 363.

127. Quintiliani, R., Jr., and P. Courvalin. 1996. Characterization of Tn 1547, a composite transposon flanked by the IS 16 and IS 256-like elements, that confers vancomycin resistance in Enterococcus faecalis BM4281. Gene 172: 1– 8.

128. Quintiliani, R., Jr., S. Evers, and P. Courvalin. 1993. The vanB gene confers various levels of self-transferable resistance to vancomycin in enterococci. J. Infect. Dis. 167: 1220– 1223.

129. Rende-Fournier, R.,, R. Leclercq,, M. Galimand,, J. Duval,, and P. Courvalin. 1993. Identification of the satA gene encoding a streptogramin A acetyltransferase in Enterococcus faecium BM4145. Antimicrob. Agents Chemother. 37: 2119– 2125.

130. Reynolds, P. E.Structure, biochemistry and mechanism of action of glycopeptide antibiotics. 1989. Eur. J. Clin. Microbiol. Infect. Dis. 8: 943– 950.

131. Reynolds, P. E., F. Depardieu, S. Dutka-Malen, M. Arthur, and P. Courvalin. 1994. Glycopeptide resistance mediated by the enterococcal transposon Tn l546 requires production of VanX for hydrolysis of D-alanyl-D-alanine. Mol. Microbiol. 13: 1065– 1070.

132. Rice, L. B.,, L. L. Carias,, C. J. Donskey,, and S. D. Rudin. 1998. Transferable, plasmid-mediated VanB-type glycopeptide resistance in Enterococcus faecium. Antimicrob. Agents Chemother. 42: 963– 964.

133.Ridenhour, M. B., H. M. Fletcher, J. E. Mortensen, and L. Daneo-Moore. 1996. A novel tetracycline-resistant determinant, tet(U), is encoded on plasmid pKQIO in Enterococcus faecium. Plasmid 35: 71– 80.

134. Rippere, K.,, R. Patel,, J. R. Uhl, K. E. Piper, J. M. Steckelberg, B. C. Kline, F. R. Cockerill III, and A. A. Yousten. 1998. DNA sequence resembling vanA and vanB in the vancomycin-resistant biopesticide Bacillus popilliae. J. Infect. Dis. 178: 584– 588.

135. Roberts, M. C, and S. L. Hillier. 1990. Genetic basis of tetracycline resistance in urogenital bacteria. Antimicrob. Agents Chemother. 34: 476– 478.

136. Roberts, M. C, J. Sutcliffe, P. Courvalin, L. Bogo Jensen, J. Rood, and H. Seppala. 1999. Nomenclature for macrolide and macrolide-lincosamide-streptogramin B resistance determinants. Antimicrob. Agents Chemother. 43: 2823– 2830.

137. Roper, D. I.,, T. Huyton,, A. Vagin,, and G. Dodson. 2000. The molecular basis of vancomycin resistance in clinically relevant enterococci: crystal structure of D-alanyl-D-lactate ligase (VanA). Proc. Natl. Acad. Set. USA 97: 8921– 8925.

138. Rouch, D. A., M. E. Byrne, Y. C. Kong, and R. A. Skurray. 1987. The aacA-aphD gentamicin and kanamycin resistance determinant of Tn 4001 from Staphylococcus aureus: expression and sequence analysis. J. Gen. Microbiol. 133: 3039– 3052.

139. Rybkine, T.,, J.-L. Mainardi,, W. Sougakoff,, E. Collatz,, and L. Gutmann. 1998. Penicillin-binding protein 5 sequence alterations in clinical isolates of Enterococcus faecium with different levels of β-lactam resistance. J. Infect. Dis. 178: 159– 163.

140. Shaw, K. J.,, P. N. Rather,, R. S. Hare,, and G. H. Miller. 1993. Molecular genetics of aminoglycoside resistance genes and familial relationships of the aminoglycoside-modifying enzymes. Microbiol. Rev. 57: 138– 163.

141. Shaw, W. V. 1983. Chloramphenicol acetyltransferase: enzymology and molecular biology. Crit. Rev. Biochem. 14: 1– 47.

142. Shen, L. L.,, W. E. Kohlbrenner,, D. Weigl,, and J. Baranowski. 1989. Mechanism of quinolone inhibition of DNA gyrase. Appearance of unique norfloxacin binding sites in enzyme-DNA complexes. J. Biol. Chem. 264: 2973– 2978.

143. Shinabarger, D. L.,, K. R. Marotti,, R. W. Murray,, A. H. Lin,, E. P. Melchior,, S. M. Swaney,, D. S. Dunyak,, W. R Demyan,, and J. M. Buysse. 1997. Mechanism of action of oxazolidinones: effects of linezolid and eperezolid on translation reactions. Antimicrob. Agents Chemother. 41: 2132– 2136.

144.Sifaoui, E, and L. Gutmann. 1997. Vancomycin dependence in a VanA-producing Enterococcus avium strain with a nonsense mutation in the natural D-Ala: D-Ala ligase gene. Antimicrob. Agents Chemother. 41: 1409.

145.Signoretto, C, M. Boaretti, and P. Canepari. 1998. Peptidoglycan synthesis by Enterococcus faecalis penicillin binding protein 5. Arch Microbiol. 170: 185– 190.

146. Soltani, M.,, D. Beighton,, J. Philpott-Howard,, and N. Woodford. 2000. Mechanisms of resistance to quinupristin-dalfopristin among isolates of Enterococcus faecium from animals, raw meat, and hospital patients in western Europe. Antimicrob. Agents Chemother. 44: 433– 436.

147. Su, Y. A.,, P. He,, and D. B. Clewell. Characterization of the tet(M) determinant of Tn 916: evidence for regulation by transcription attenuation. Antimicrob. Agents Chemother. 36: 769– 778.

148. Swaney, S. M., H. Aoki, M. Clelia Ganoza, and D. L. Shinabarger. 1998. The oxazolidinone linezolid inhibits initiation of protein synthesis in bacteria. Antimicrob. Agents Chemother. 42: 3251– 3255.

149. Tai, P., C, and B. D. Daris. 1985. The actions of antibiotics on the ribosome, p. 41– 68. In D. Greenwood, and F. O'Grady (ed.), The Scientific Basis of Antimicrobial Chemotherapy. Cambridge University Press, Cambridge, United Kingdom.

150.Tait-Kamradt, A., J. Clancy, M. Cronan, F. Dib-Hajj, L. Wondrack, W. Yuan, and J. Sutcliffe. 1997. mefE is necessary for the erythromycin-resistant M phenotype in Streptococcus pneumoniae. Antimicrob. Agents Chemother. 41: 2251– 2255.

151. Tankovic, J.,, F. Mahjoubi,, P. Courvalin,, J. Duval,, and R. Leclercq. 1996. Development of fluoroquinolone resistance in Enterococcus faecalis and role of mutations in the DNA gyrase gyrA gene. Antimicrob. Agents Chemother. 40: 2558– 2561.

152. Thomas, W. D., Jr., and G. D. Archer. 1989. Mobility of gentamicin resistance genes from staphylococci isolated in the United States: identification of Tn 4031, a gentamicin resistance transposon from Staphylococcus epidermidis. Antimicrob. Agents Chemother. 33: 1335– 1341.

153. Thompson, R. R.,, J. Schwartzenhauer,, D. W. Hughes,, A. M. Berghuis,, and G. D. Wright. 1999. The COOH terminus of aminoglycoside phosphotransferase (3')-IIIa is critical for antibiotic recognition and resistance. J. Biol. Chem. 274: 30697– 30706.

154. Tomayko, J. F., K. K. Zscheck, K. V. Singh, and B. E. Murray. 1996. Comparison of the β-lactamase gene cluster in clonally distinct strains of Enterococcus faecalis. Antimicrob. Agents Chemother. 40: 1170– 1174.

155. Tornieporth, N. G.,, R. B. Roberts,, J. John,, A. Hafner,, and L. W. Riley. 1996. Risk factors associated with vancomycin-resistant Enterococcus faecium infection or colonization in 145 matched case patients and control patients. Clin. Infect. Dis. 23: 767– 772.

156.Torres Viera, C, S. Tsiodras, H. S. Gold, E. R G. Coakley, C. Wennersten, G. M. Eliopoulos, R. C. Moellering, Jr., and R. T. Inouye. 2001. Restoration of vancomycin susceptibility in Enterococcus faecalis by antiresistance determinant gene transfer. Antimicrob. Agents Chemother. 45: 973– 975.

157.Trieu-Cuot, R, and R Courvalin. 1983. Nucleotide sequence of the Streptococcus faecalis plasmid gene encoding the 3' 5"-aminoglycoside phosphotransferase type III. Gene 23: 331– 341.

158. Trieu-Cuot, P.,, G. de Cespédès, F. Bentorcha, F. Delbos, E. Gaspar, and T. Horaud. 1993. Study of heterogeneity of chloramphenicol acetyltransferase (CAT) genes in streptococci and enterococci by polymerase chain reaction: characterization of a new CAT determinant. Antimicrob. Agents Chemother. 37: 2593– 2598.

159. Tsai, S. F., M. J. Zervos, D. B. Clewell, S. M. Donabedian, D. F. Sahm, and J. W. Chow. 1998. A new high-level gentamicin resistance gene, aph(2")-Id, in Enterococcus sp. Antimicrob. Agents Chemother. 42: 1229– 1232.

160. Uttley, A. H.,, C. H. Collins,, J. Naidoo,, and R. C. George. 1988. Vancomycin-resistant enterococci [letter]. Lancet 1: 57– 58.

161. Van Bambeke, F.,, M. Chauvel,, P. E. Reynolds,, H. S. Fraimow,, and P. Courvalin. 1999. Vancomycin-dependent Enterococcus faecalis clinical isolates and revertant mutants. Antimicrob. Agents Chemother. 43: 41– 47.

162. Vannuffel, P.,, M. Di Giambattista,, and C. Cocito. 1992. The role of rRNA bases in the interaction of peptidyltransferase inhibitors with bacterial ribosomes. J. Biol. Chem. 267: 16114– 16120.

163. Vannuffel, P.,, M. Di Giambattista,, and C. Cocito. 1994. Chemical probing of virginiamycin M-promoted conformational change of the peptidyltransferase domain. Nucleic Acids Res. 22: 4449– 4453.

164. Walsh, C. T.,, S. L. Fisher,, I. S. Park,, M. Parhlad,, and Z. Wu. 1996. Bacterial resistance to vancomycin: five genes and one missing hydrogen bond tell the story. Chem. Biol. 3: 21– 28.

165. Wang, J. C. 1996. DNA topoisomerases. Annu. Rev. Biochem. 65: 635– 692.

166. Weisblum, B. 1995. Erythromycin resistance by ribosome modification. Antimicrob. Agents Chemother. 39: 577– 585.

167. Wennersten, C. B.,, and R. C. Moellering,, Jr. 1980. Mechanism of resistance to pemdllm-aminoglycoside synergism in Streptococcus faecium, p. 710– 712. In J. Nelson, and C. Grassi (ed.), Current Chemotherapy and Infectious Diseases. American Society for Microbiology, Washington, D.C.

168. Werner, G.,, and W. Witte. 1999. Characterization of a new enterococcal gene, satG, encoding a putative acetyltransferase conferring resistance to streptogramin A compounds. Antimicrob. Agents Chemother. 43: 1813– 1814.

169. Williamson, R.,, S. Al-Obeid,, J. H. Shlaes,, F. W. Goldstein,, and D. M. Shlaes. 1989. Inducible resistance to vancomycin in Enterococcus faecium D366. J. Infect. Dis. 159: 1095– 1104.

170. Williamson, R.,, L. Gutmann,, T. Horaud,, F. Delbos,, and J. F. Acar. 1985. Use of penicillin-binding proteins for the identification of enterococci. J. Gen. Microbiol. 132: 1929– 1937.

171. Wright, G. D.,, and P. Ladak. 1997. Overexpression and characterization of the chromosomal aminoglycoside 6'- N-acetyltransferase from Enterococcus faecium. Antimicrob. Agents Chemother. 41: 956– 960.

172. Xiong, L.,, P. Kloss,, S. Doughwaite,, N. Meller Andersen,, S. Swaney,, D. L. Shinabarger,, and A. S. Mankin. 2000. Oxazolidinone resistance mutations in 23S rRNA of Escherichia coli reveal the central region of domain V as the primary site of drug action. J. Bacteriol. 182: 5325– 5331.

172a. Zervos, M. J.,, and J. W. Chow. Unpublished data.

173. Zilhao, R.,, B. Papadopoulou,, and P. Courvalin. 1988. Occurrence of the Campylobacter resistance gene tetO in Enterococcus and Streptococcus spp. Antimicrob. Agents Chemother. 32: 1793– 1796.

174. Zimmermann, R. A., R. C. Moellering, Jr., and A. N. Weinberg. 1971. Mechanism of resistance to antibiotic synergism in enterococci. J. Bacteriol. 105: 873– 879.

175. Zorzi, W.,, X. Y. Zhou,, O. Dardenne,, J. Lamotte,, D. Raze,, J. Pierre,, L. Gutmann,, and J. Coyette. 1996. Structure of the low-affinity penicillin-binding protein 5 PBP5fm in wild-type and highly penicillin-resistant strains of Enterococcus faecium. J. Bacteriol. 178: 4948– 4957.

176. Zscheck, K. K.,, and B. E. Murray. 1993. Genes involved in the regulation of β-lactamase production in enterococci and staphylococci. Antimicrob. Agents Chemother. 37: 1966– 1970.

177. Zurenko, G.E.,, W.M. Todd,, B. Hafkin,, B. Meyers,, C. Kauffman,, J. Bock,, J. Slightom,andD.Shinabarger. 1999. Development of linezolid-resistant Enterococcus faecium in two compassionate use program patients treated with linezolid, abstr. 848, p. 117. In Abstracts of the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C.

Tables

Acquired Antibiotic Resistances in Enterococci

/content/10.1128/9781555817923.chap9.tab9-1

Table 1

Overview of vancomycin resistance genotypes a

10.1128/9781555817923/tab9-1_thmb.gif

10.1128/9781555817923/tab9-1.gif

Table 1

Overview of vancomycin resistance genotypes a

/content/10.1128/9781555817923.chap9.tab9-2

Table 2

Overview of gene functions in vanA operon a

10.1128/9781555817923/tab9-2_thmb.gif

10.1128/9781555817923/tab9-2.gif

Table 2

Overview of gene functions in vanA operon a