Preliminary genotyping in 105 strains of Mycobacterium tuberclosis isolated from Fujian province by variable number tandem repeat analysis

A new method based on the variable number tandem repeat(VNTR) analysis was applied for the genotyping of Mycobacterium tuberculosis,in which NNTRs from 12 loci with good genotyping efficiency were selected,and a rapid finger-printing method was established by PCR and agarose gel electrophoresis used to analyze the DNA polymorphism of drug-resistant M.tuberculosis.The polymorphism of the DNA finger-printing of M.tuberculosis was analyzed with BioNumerics software(Version 4.5).Based on the characteristics of the PCR-amplified finger-prints obtained,the 105 strains of M.tuberculosis isolated from Fujian province which were detected in 12 VNTR loci,could be classified into 4 genetic types,in which type 1 was the predominant genotype.The percentages of type 1,II,III and IV were 66.7%(70/105),20.0%(21/105), 9.5%(10/105) and 3.8%(4/105) respectively.These results indicate that the transmission of tuberculosis in Fujian province is mainly due to M.tuberculosis type I and the surveillance on this type of microorganism needs to be strengthened.