Enterococcus faecium UCN71, isolated from a blood culture, was resistant to low levels of vancomycin (MIC, 16 g/ml) but susceptible to teicoplanin (MIC, 0.5 g/ml). No amplification was observed with primers specific for the previously described glycopeptide resistance ligase genes, but a PCR product corresponding to a gene called vanN was obtained using degenerate primers and was sequenced. The glycopeptide antibiotics vancomycin and teicoplanin are widely used for the treatment of severe infections due to Gram-positive bacteria and act by inhibition of peptidoglycan synthesis. Glycopeptides bind to the C-terminal D-alanyl-Dalanine of late peptidoglycan precursors and block the following steps in cell wall assembly (14).During the past two decades, glycopeptide-resistant enterococci (GRE), in particular Enterococcus faecium, have spread as multiresistant opportunistic pathogens in hospitals worldwide. Since the first descriptions of vancomycin resistance in E. faecium in 1988 (24, 38), eight operons that confer resistance to glycopeptides have been distinguished on the basis of the sequence of the structural gene for the resistance ligase. They are designated according to the gene that encodes either a D-alanyl-D-lactate (vanA, vanB, vanD, and vanM) or a D-alanyl-D-serine (vanC, vanE, vanG, and vanL) ligase (14, 8, 40) (8,11,14). VanG is the only transferable D-Ala-D-Ser resistance type characterized so far (12).E. faecium UCN71 was resistant to low levels of vancomycin and susceptible to teicoplanin but did not harbor any known vancomycin resistance ligase gene. We present evidence that resistance to vancomycin in this clinical isolate is due to a new type of determinant, named VanN. Phenotypic and genotypic traits of VanN resistance were identified, and transferability was assessed. MATERIALS AND METHODSStrains. The characteristics of the strains are listed in Table 1. E. faecium UCN71 and E. faecium UCN72 were isolated in 2008 from a blood culture and a rectal swab, respectively, of a patient at the Paoli-Calmettes Institute, Marseille, France. E. faecium BM4107 (24) and E. faecalis JH2-2 (22), which are resistant to fusidic acid and rifampin, were used as recipients in conjugation experiments. VanG-type E. faecalis BM4518 (12) was used as a reference for analysis of peptidoglycan precursors.Antibiotic susceptibility testing. MICs were determined by the broth microdilution technique recommended by the Comité de l'Antibiogramme de la Société Française de Microbiologie (10). Plates were incubated for 24 h at 37°C before being read.Molecular typing. Clinical isolates were typed by pulsed-field gel electrophoresis (PFGE) of genomic DNA using a CHEF II Mapper system (Bio-Rad, Marnes-la-Coquette, France) as described previously (36). Total DNA digested with SmaI was subjected to electrophoresis (6 V/cm, 22 h, pulse times of 5 to 30 s at 14°C) in an agarose gel.Multilocus sequence typing (MLST) of E. faecium was performed as previously

The national mandatory notification of unusual nosocomial events allowed rapid identification of VRE outbreaks and early implementation of control measures that have proved effective. However, VRE continue to emerge in a growing number of hospitals.

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The antimicrobial susceptibilities of 30 Rhodococcus equi isolates obtained from 30 patients between 1993 and 2001 in northern Thailand were investigated. The MICs showed a tendency toward resistance to various antibiotics but sensitivity to imipenem, minocycline, vancomycin, and teicoplanin (MICs, <0.5 g/ml) and relative sensitivity to meropenem, clarithromycin, and ciprofloxacin (MICs, <2 g/ml). Of the 30 isolates, 26 were susceptible (MICs, <1 g/ml), 1 showed low-level resistance (MIC, 8 g/ml), and 3 showed high-level resistance (MICs, >64 g/ml) to rifampin. PCR amplification and DNA sequencing of the rpoB gene and molecular typing by pulsed-field gel electrophoresis (PFGE) were performed for eight R. equi isolates from eight AIDS patients with pneumonia or lung abscess caused by R. equi between 1998 and 2001, including one low-and three highlevel rifampin-resistant isolates. As a result, two high-level rifampin-resistant strains with PFGE pattern A had a Ser531Trp (Escherichia coli numbering) mutation, and one high-level rifampin-resistant strain with PFGE pattern B had a His526Tyr mutation, whereas one low-level rifampin-resistant strain with PFGE pattern C had a Ser509Pro mutation. Four rifampin-susceptible strains with PFGE patterns D and E showed an absence of mutation in the rpoB region. Our results indicate the presence of several types of rifampin-resistant R. equi strains among AIDS patients in northern Thailand.