Transposons glycopeptide resistance

Acquired resistance to the glycopeptides is transposon-mediated and has so far been largely confined to the enterococci. This has been a problem clinically because many of these strains have been resistant to all other antibiotics and were thus effectively untreatable. Fortunately, the enterococci are not particularly pathogenic and infections have been confined largely to seriously ill, long-term hospital patients. Two types of acquired glycopeptide resistance have been described (Woodford et al. 1995). The VanA phenotype is resistant to vancomycin and teicoplanin, whereas VanB is resistant... 

Fig. 9.4 Organization of glycopeptide-resistance genes in transposon Tnl546. IR, invested repeats HPK, histidine protein kinase TcR, low level teicoplanin resistance.

Arthur, M. Molinas, C. Depardieu, E Courvalin, P Characterization of Tnl546, a Tn3-related transposon conferring glycopeptide resistance by synthesis of depsipeptide peptidoglycan precursors in Enterococcus faecium BM4147. J. Bacteriol., 175, 117-127 (1993)... 

PE Reynolds, F Depardieu, S Dutka-Malen, M Arthur, P Courvalin. Glycopeptide resistance mediated by enterococcal transposon Tnl546 requires production of VanX for hydrolysis of D-alanyl-D-alanine. Mol Microbiol 13, 1065-1070, 1994. 

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