760. The Diversity of Mycobacterium tuberculosis in India Is Underestimated and Underreported

Abstract

BackgroundThe seven lineages of Mycobacterium tuberculosis differ in virulence, transmissibility, drug resistance, and immune responses. We reviewed spoligotype data published from India to determine the distribution and diversity of TB lineages in India.MethodsSpoligoytpe patterns were extracted from studies published from India and compared against the SpolSimilarity database to determine Spoligotype International Type (SIT) number, sub-lineage and lineage. Minimum spanning trees (MSTs) were created with Phyloviz.ResultsThirty-four studies list 1,473 spoligotypes containing 8,242 isolates (Table 1), with 6,733 isolates belonging to 472 SITs. Of the remaining 1,001 patterns (1,509 isolates), 351 patterns (491 isolates) match orphans, while 650 patterns (1,018 isolates) are unreported; these 1,509 isolates could potentially form 532 new SITs and 469 orphans. The most common SITs are SIT11 (Lineage 1; 1,218 isolates, 14.78%), SIT26 (Lineage 3; 982,11.91%) and SIT1 (Lineage 2; 618, 7.5%). Figure 1 demonstrates regional differences in lineage distribution. Figure 2 is an MST of all isolates by lineage (“not assigned” are known SITs with no lineage and “unknowns” are previously unreported patterns). Figure 3 is an MST by superfamily, “others” referring to patterns with no known superfamily.ConclusionLineages 1 and 3 dominate in India, in contrast to lineages 2 and 4 prevalent worldwide. The 1,473 SITs reflect the significant diversity of M. tuberculosis in India; the 1,001 orphan and previously unreported patterns suggest this diversity is underestimated. Understanding M. tuberculosis diversity is necessary for clinical and public health interventions to control India’s TB epidemic.Table 1.LineageSuperfamilyNumber of SITsNumber of IsolatesPercentage (%)Lineage 1EAI2343,21439.00Manu704815.84Total3043,69544.83Lineage 2Beijing116557.95Lineage 3CAS1821,86522.63Lineage 4H26891.08LAM20550.67S5130.16T1114765.78Ural11370.45X17560.68Total1907268.81UnknownUnknown7861,30115.79Total1,4738,242100.00Figure 1.Figure 2.Figure 3.Disclosures All authors: No reported disclosures.