SYBR[R]Green qPCR was performed on DNAs extracted from seven reference strains as positive controls for the seven possible genes, including asal, GelE, cylA, esp, hyl, VanA, and VanB
. Specific primers designed using a reference for seven gene sequences representing asal, GelE, cylA, esp, hyl, VanA, and VanB
were collected from the GenBank database.
The mechanism of resistance for both vanA and vanB
genes encompass three sets of enzymes harbored by glycopeptide-producing bacteria.
Until now, nine types of resistance genes have been identified for the genus enterococcus: VanA, VanB
, VanC, VanD, VanE, VanG, VanL, VanM and VanN.
All 15 isolates screened were negative for the other antibiotic resistance genes, which correlated well with their susceptibility phenotypes: vancomycin (vanA and vanB
genes), mupirocin (mupA, ileS), gentamicin (aac(6')-aph(2")), linezolid (cfr), tetracycline (tetA, tetB), and fusidic acid fusB, fusC, fusD).
BC-GP detected 14/14 (100%) vanA and 20/20 (100%) vanB
genes in well-characterized VRE strains from previous studies in Japan.
14) in cluster 1 was PCRpositive for the vanB
gene, but still shared high homology with the other two isolates, which were both vanA-positive.
The isolates were found to be positive for the presence of the vanA genotype; vanB
and vanC2 gene products could not be amplified by using polymerase chain reaction.
The BD GeneOhm(tm) VanR Assay is a qualitative in vitro test for the rapid detection of vancomycin-resistance (vanA and vanB
) genes directly from perianal swabs.
For a discussion of the presumption for or against preemption based on historic presence in the field, see Clare Huntington, The Constitutional Dimension of Immigration Federalism, 61 VANB
faecalis), a vanB
gene cluster-carrying strain], and E.