Spoligotypes of Mycobacterium tuberculosis isolates of a high tuberculosis burden aboriginal township in Taiwan

To understand the genotype of Mycobacterium tuberculosis isolates circulating in the aboriginal Sioulin Township, the highest tuberculosis (TB) endemic area in Taiwan, a total of 138 isolates were collected between January 2003 and December 2004 for genotyping. Genotyping consisted of spacer oligonucleotide typing (spoligotyping), IS6110-restriction fragment length polymorphism (RFLP) and mgtC and ogt single nucleotide polymorphisms (SNPs) characterizations. Spoligotyping data were compared with those from the fourth international spoligotyping database, SpolDB4. Of 27 resolved spoligotypes, 14 spoligotype patterns matched those found in SpolDB4 and 13 (TW1-13) were identified as novel. The most common among the 14 defined spoligotypes was Beijing ST1 (35.5%, 49/138), followed by Haarlem ST742 (10.9%, 15/138), Latin-American-Mediterranean (LAM) ST33 (5.8%, 8/138) and Haarlem ST50 (3.6%, 5/138). Of the 13 novel spoligotypes, 5 (TW 6-8, 12 and 13) were identified as "Haarlem-like" lineages according to clade analyses of spoligotyping and RFLP dendrograms. Overall, major spoligotypes found in Sioulin Township were Haarlem and Haarlem-like (39.1%), Beijing (38.4%), and LAM (5.8%) lineages. Interestingly, the results did not indicate any East-African-Indian lineages, which are highly prevalent in Far-East Asia. Our data also contained the first evidence of ST33 (LAM3 lineage) in Asia. This study provides first depiction of molecular epidemiology of M. tuberculosis in this isolated aboriginal population and further elucidation of the global historical expansion of the isolates.