No abstract

Background: Tuberculosis (TB) remains the number one killer infectious disease in developing countries. There were an estimated 8.8 million incident cases of TB (range, 8.5 million-9.2 million) globally in 2010. Most of the estimated number of cases in 2010 occurred in Asia (59%) and Africa (26%). India alone accounted for an estimated one quarter (26%) of all TB cases worldwide. The clinical manifestations of TB could be either Pulmonary or Extra pulmonary (EPTB), the former being the commonest. In India, EPTB accounts for 10 to 15 percent of all types of TB. Mycobacterium tuberculosis complex shares high genomic similarities. Genotyping of M. tuberculosis helps in tracking the transmission links between individuals, and demonstrated instances in which epidemiologically linked people were in fact, infected with unrelated strains.Methods: Spacer-oligonucleotide typing and 12 loci mycobacterial interspersed repetitive units (MIRU) were performed to find genetic profiles of M. tuberculosis strains isolated from extrapulmonary tuberculosis patients. The spoligotyping results were compared with the world Spoligotyping Database of Institute Pasteur de Guadeloupe (SpolDB4). One hundred twenty five isolates of extrapulmonary tuberculosis were characterized and their drug susceptibility test (DST) was performed using BACTEC MGIT 960Results: Based on the spoligotyping method, 110 strains displayed known patterns and 15 isolates were absent in the database. Predominant spoligotypes belonged to the CAS family (57.27%). Overall, 28 different patterns were identified, including 12 clusters and 16 unique patterns. The largest clade comprised 38 strains belonging to the CAS1 DEL lineage. The combination of spoligotyping and 12-loci MIRU demonstrated maximal discriminatory power. We observed a significant association between Beijing family strains and drug-resistance. Conclusion:The present study demonstrated that CAS family isolates were the most prevalent genotype in extrapulmonary tuberculosis. Spoligotyping in combination with 12-loci MIRU is the most discriminatory tool for epidemiological analysis of M. tuberculosis from extrapulmonary tuberculosis.