Validation of ten new polymorphic tandem repeat loci and application to the MLVA typing of Burkholderia pseudomallei isolates collected in Singapore from 1988 to 2004

Multiple locus variable number of tandem repeat (VNTR) analysis (MLVA) has been shown to be very promising for the typing of Burkholderia pseudomallei and mallei. The currently available set of loci requires high resolution allele size measurement due to short repeat units. The present work was aimed at expanding the available set of VNTR loci, and generating data from a collection of 102 B. pseudomallei strains isolated in Singapore between 1988 and 2004 including few additional strains of various origins as references. Ten new VNTRs with a longer array size have been identified compatible with standard agarose gel separation, and a reference database of 72 genotypes was created which can be queried on the Internet.