16. Krogstad DJ, Pargwette AR. Defective killing of enterococci: a common property of antimicrobial agents acting on the cell wall. Antimicrob Agents Chemother 1980; 17:965-8; PMID:6902640 17. Hodges TL, Zighelboim-Daum S, Eliopoulos GM, Wennersten C, Moellering RC, Jr.. Antimicrobial susceptibility changes in Enterococcus faecalis follow- ing various penicillin exposure regimens. Antimicrob Agents Chemother 1992; 36:121-5; PMID:1590676 18. Zimmermann RA, Moellering RC, Jr., Weinberg AN. Mechanism of resistance to antibiotic synergism in enterococci. J Bacteriol 1971; 105:873-9; PMID: 4994038 19. Moellering RC, Jr., Weinberg AN. Studies on antibiotic syngerism against enterococci. II. Effect of various antibiotics on the uptake of 14 C-labeled streptomycin by enterococci. J Clin Invest 1971; 50: 2580-4; PMID:5001959; http://dx.doi.org/10.1172/ JCI106758 20. Geraci JE, Martin WJ. Antibiotic therapy of bacterial endocarditis. VI. Subacute enterococcal endocarditis; clinical, pathologic and therapeutic consideration of 33 cases. Circulation 1954; 10:173-94; PMID:13182750; http://dx.doi.org/10.1161/01.CIR.10.2.173 21. Costa Y, Galimand M, Leclercq R, Duval J, Courvalin P. Characterization of the chromosomal aac(6')-Ii gene specific for Enterococcus faecium. Antimicrob Agents Chemother 1993; 37:1896-903; PMID:8239603 22. Galimand M, Schmitt E, Panvert M, Desmolaize B, Douthwaite S, Mechulam Y, et al. Intrinsic resistance to aminoglycosides in Enterococcus faecium is con- ferred by the 16S rRNA m5C1404-specific methyl- transferase EfmM. RNA 2011; 17:251-62; PMID: 21159796; http://dx.doi.org/10.1261/rna.2233511 23. Arias CA, Contreras GA, Murray BE. Management of multidrug-resistant enterococcal infections. Clin Microbiol Infect 2010; 16:555-62; PMID:20569266; http://dx.doi.org/10.1111/j.1469-0691.2010.03214.x 24. Singh KV, Weinstock GM, Murray BE. An Enterococcus faecalis ABC homologue (Lsa) is required for the resistance of this species to clindamycin and quinupristin-dalfopristin. Antimicrob Agents Chemother 2002; 46:1845-50; PMID:12019099; http://dx.doi.org/10.1128/AAC.46.6.1845-1850.2002 25. Portillo A, Ruiz-Larrea F, Zarazaga M, Alonso A, Martinez JL, Torres C. Macrolide resistance genes in Enterococcus spp. Antimicrob Agents Chemother 2000; 44:967-71; PMID:10722498; http://dx.doi. org/10.1128/AAC.44.4.967-971.2000 26. Bushby SR, Hitchings GH. Trimethoprim, a sulphon- amide potentiator. Br J Pharmacol Chemother 1968; 33:72-90; PMID:5301731 27. Zervos MJ, Schaberg DR. Reversal of the in vitro susceptibility of enterococci to trimethoprim-sulfa- methoxazole by folinic acid. Antimicrob Agents Chemother 1985; 28:446-8; PMID:3935044 28. Grayson ML, Thauvin-Eliopoulos C, Eliopoulos GM, Yao JD, DeAngelis DV, Walton L, et al. Failure of trimethoprim-sulfamethoxazole therapy in experi- mental enterococcal endocarditis. Antimicrob Agents Chemother 1990; 34:1792-4; PMID:2126691 29. Chenoweth CE, Robinson KA, Schaberg DR. Efficacy of ampicillin versus trimethoprim-sulfamethoxazole in a mouse model of lethal enterococcal peritonitis. Antimicrob Agents Chemother 1990; 34:1800-2; PMID:2126692 30. Palmer KL, Kos VN, Gilmore MS. Horizontal gene transfer and the genomics of enterococcal antibiotic resistance. Curr Opin Microbiol 2010; 13:632-9; PMID:20837397; http:// dx.doi.org/10.1016/j.mib.2010.08.004 31. Hegstad K, Mikalsen T, Coque TM, Werner G, Sundsfjord A. Mobile genetic elements and their contribution to the emergence of antimicrobial resistant Enterococcus faecalis and Enterococcus faecium. Clin microbiol infect 2010; 16:541-54; PMID:20569265; http://dx.doi.org/10.1111/j.1469- 0691.2010.03226.x 32. Wardal E, Sadowy E, Hryniewicz W. Complex nature of enterococcal pheromone-responsive plasmids. Polish J Microbiol 2010; 597987. 33. Périchon B, Courvalin P. VanA-type vancomycin- resistant Staphylococcus aureus. Antimicrob Agents Chemother 2009; 53:4580-7; PMID:19506057; http://dx.doi.org/10.1128/AAC.00346-09 34. Rice LB. Tn916 family conjugative transposons and dissemination of antimicrobial resistance determinants. Antimicrob Agents Chemother 1998; 42:1871-7; PMID:9687377 35. Murray BE, Mederski-Samaroj B. Transferable beta- lactamase. A new mechanism for in vitro penicillin resistance in Streptococcus faecalis. J Clin Invest 1983; 72:1168-71; PMID:6411768; http://dx.doi.org/10. 1172/JCI111042 36. Fontana R, Ligozzi M, Pittaluga F, Satta G. Intrinsic penicillin resistance in enterococci. Microb Drug Resist 1996; 2:209-13; PMID:9158761; http://dx. doi.org/10.1089/mdr.1996.2.209 37. Rice LB, Bellais S, Carias LL, Hutton-Thomas R, Bonomo RA, Caspers P, et al. Impact of specific pbp5 mutations on expression of beta-lactam resistance in Enterococcus faecium. Antimicrob Agents Chemother 2004; 48:3028-32; PMID:15273117; http://dx.doi. org/10.1128/AAC.48.8.3028-3032.2004 38. Ono S, Muratani T, Matsumoto T. Mechanisms of resistance to imipenem and ampicillin in Enterococcus faecalis. Antimicrob Agents Chemother 2005; 49: 2954-8; PMID:15980374; http://dx.doi.org/10.1128/ AAC.49.7.2954-2958.2005 39. Rice LB, Carias LL, Rudin S, Lakticová V, Wood A, Hutton-Thomas R. Enterococcus faecium low-affinity pbp5 is a transferable determinant. Antimicrob Agents Chemother 2005; 49:5007-12; PMID:16304165; http://dx.doi.org/10.1128/AAC.49.12.5007-5012.2005 40. Clark C, McGhee P, Appelbaum PC, Kosowska-Shick K. Multistep resistance development studies of ceftaro- line in gram-positive and -negative bacteria. Antimicrob Agents Chemother 2011; 55:2344-51; PMID:21343467; http://dx.doi.org/10.1128/AAC. 01602-10 41. Arias CA, Singh KV, Panesso D, Murray BE. Evaluation of ceftobiprole medocaril against Enterococcus faecalis in a mouse peritonitis model. J Antimicrob Chemother 2007; 60:594-8; PMID: 17606481; http://dx.doi.org/10.1093/jac/dkm237 42. Arias CA, Singh KV, Panesso D, Murray BE. Time-kill and synergism studies of ceftobiprole against Enterococcus faecalis, including beta-lactamase-pro- ducing and vancomycin-resistant isolates. Antimicrob Agents Chemother 2007; 51:2043-7; PMID: 17438057; http://dx.doi.org/10.1128/AAC.00131-07 43. Lascols C, Legrand P, Mérens A, Leclercq R, Muller- Serieys C, Drugeon HB, et al. In vitro antibacterial activity of ceftobiprole against clinical isolates from French teaching hospitals: proposition of zone dia- meter breakpoints. Int J Antimicrob Agents 2011; 37: 235-9; PMID:21295447; http://dx.doi.org/10.1016/j. ijantimicag.2010.11.035 44. Henry X, Amoroso A, Coyette J, Joris B. Interaction of ceftobiprole with the low-affinity PBP 5 of Enterococcus faecium. Antimicrob Agents Chemother 2010; 54:953-5; PMID:19917749; http://dx.doi.org/10.1128/AAC.00983-09 45. Mederski-Samoraj BD, Murray BE. High-level resist- ance to gentamicin in clinical isolates of enterococci. J Infect Dis 1983; 147:751-7; PMID:6404994; http:// dx.doi.org/10.1093/infdis/147.4.751 46. Ferretti JJ, Gilmore KS, Courvalin P. Nucleotide sequence analysis of the gene specifying the bifunc- tional 6'-aminoglycoside acetyltransferase 2' -aminogly- coside phosphotransferase enzyme in Streptococcus faecalis and identification and cloning of gene regions specifying the two activities. J Bacteriol 1986; 167: 631-8; PMID:3015884 47. Courvalin P, Carlier C, Collatz E. Plasmid-mediated resistance to aminocyclitol antibiotics in group D streptococci. J Bacteriol 1980; 143:541-51; PMID: 6259117 48. Chow JW. Aminoglycoside resistance in enterococci. Clin Infect Dis 2000; 31:586-9; PMID:10987725; http://dx.doi.org/10.1086/313949 49. Chow JW, Zervos MJ, Lerner SA, Thal LA, Donabedian SM, Jaworski DD, et al. A novel gentamicin resistance gene in Enterococcus. Antimicrob Agents Chemother 1997; 41:511-4; PMID:9055984 50. Mahbub Alam M, Kobayashi N, Ishino M, Sumi A, Kobayashi K, Uehara N, et al. Detection of a novel aph (2'') allele (aph[2'']-Ie) conferring high-level gentamicin resistance and a spectinomycin resistance gene ant(9)- Ia (aad 9) in clinical isolates of enterococci. Microb Drug Resist 2005; 11:239-47; PMID:16201926; http://dx.doi.org/10.1089/mdr.2005.11.239 51. Tsai SF, Zervos MJ, Clewell DB, Donabedian SM, Sahm DF, Chow JW. A new high-level gentamicin resistance gene, aph(2'')-Id, in Enterococcus spp. Antimicrob Agents Chemother 1998; 42:1229-32; PMID:9593155 52. Hollingshead S, Vapnek D. Nucleotide sequence analysis of a gene encoding a streptomycin/spectino- mycin adenylyltransferase. Plasmid 1985; 13:17-30; PMID:2986186; http://dx.doi.org/10.1016/0147- 619X(85)90052-6 53. Eliopoulos GM, Farber BF, Murray BE, Wennersten C, Moellering RC, Jr.. Ribosomal resistance of clinical enterococcal to streptomycin isolates. Antimicrob Agents Chemother 1984; 25:398-9; PMID:6326668 54. Trieu-Cuot P, Courvalin P. Nucleotide sequence of the Streptococcus faecalis plasmid gene encoding the 3'5''-aminoglycoside phosphotransferase type III. Gene 1983; 23:331-41; PMID:6313476; http://dx.doi.org/ 10.1016/0378-1119(83)90022-7 55. Carlier C, Courvalin P. Emergence of 4',4''-aminogly- coside nucleotidyltransferase in enterococci. Antimicrob Agents Chemother 1990; 34:1565-9; PMID:2171424 56. Farrell DJ, Mendes RE, Ross JE, Sader HS, Jones RN. LEADER Program results for 2009: an activity and spectrum analysis of linezolid using 6,414 clinical isolates from 56 medical centers in the United States. Antimicrob Agents Chemother 2011; 55:3684-90; PMID: 21670176; http://dx.doi.org/10.1128/AAC.01729-10 57. Arthur M, Courvalin P. Genetics and mechanisms of glycopeptide resistance in enterococci. Antimicrob Agents Chemother 1993; 37:1563-71; PMID:8215264 58. Gold HS. Vancomycin-resistant enterococci: mechanisms and clinical observations. Clin Infect Dis 2001; 33:210-9; PMID:11418881; http://dx.doi.org/10.1086/321815 59. Reynolds PE, Depardieu F, Dutka-Malen S, Arthur M, Courvalin P. Glycopeptide resistance mediated by enterococcal transposon Tn1546 requires production of VanX for hydrolysis of D-alanyl-D-alanine. Mol Microbiol 1994; 13:1065-70; PMID:7854121; http:// dx.doi.org/10.1111/j.1365-2958.1994.tb00497.x 60. Reynolds PE, Arias CA, Courvalin P. Gene vanXYC encodes D,D -dipeptidase (VanX) and D,D-carboxy- peptidase (VanY) activities in vancomycin-resistant Enterococcus gallinarum BM4174. Mol Microbiol 1999; 34:341-9; PMID:10564477; http://dx.doi.org/ 10.1046/j.1365-2958.1999.01604.x 430 Virulence Volume 3 Issue 5