Study on genityping of Mycobacterium tuberculosis strains isolated from patients of rural origin with variable number tandem repeat

  Objective   To characterize the My cobacterium tuberculosis(M.TB)isolates recovered from tuberculosis patients of rual morth Jiangsu province with variable-numbertandem-repeat(VNT R)genoty ping, and analyze factors related to the dominant VNTRgenotype.

  Methods   Five ex act tandem repeat(ETR-A~ETR-E)loci were amplified by PCRand run on a Caliper1 000 analy zerforall the isolates.VNTRgenotype forevery isolates were creared by the copy numberof each tandem repeats determind according to the size of PCRproducts.

  Results   Atotal of 37 different allele ptofiles were identified by the VN TRforall the 101 isolates fell into 15 clusters.38.6% of the strains studied were dominant VNTRpattern 42435, VNT R 42435 was not significantly associated with resistance to all the fourdrugs and BCGvaccination.

  Conclusion   VN TRtypingis a simple and rapid tool which generates numerical genotypes, It does enable M.TBisolates to be grouped into distinct groups.The advantages of the VNT R 42435 pattern cannot be considered to be coming from some drugresistanges o rBCGvaccination.