760. The Diversity of Mycobacterium tuberculosis in India is Underestimated and Underreported
Session: Poster Abstract Session: Tuberculosis and Other Mycobacterial Infections
Thursday, October 4, 2018
Room: S Poster Hall

Background:

The 7 lineages of Mycobacterium tuberculosis (M.tb) 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.

Methods:

Spoligoytpe 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.

Results:

34 studies list 1473 spoligotypes containing 8242 isolates (Table 1), with 6733 isolates belonging to 472 SITs. Of the remaining 1001 patterns (1509 isolates), 351 patterns (491 isolates) match orphans, while 650 patterns (1018 isolates) are unreported; these 1509 isolates could potentially form 532 new SITs and 469 orphans. The most common SITs are SIT11 (Lineage 1; 1218 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.

Conclusion:

Lineages 1 and 3 dominate in India, in contrast to lineages 2 and 4 prevalent worldwide. The 1473 SITs reflect the significant diversity of M.tb  in India; the 1001 orphan and previously unreported patterns suggest this diversity is underestimated. Understanding M.tb diversity is  necessary for clinical and public health interventions to control India’s TB epidemic.

Table 1:

Lineage

Superfamily

Number of SITs

Number of isolates

Percentage (%)

Lineage 1

EAI

234

3214

39.00

Manu

70

481

5.84

Total

304

3695

44.83

Lineage 2

Beijing

11

655

7.95

Lineage 3

CAS

182

1865

22.63

Lineage 4

H

26

89

1.08

LAM

20

55

0.67

S

5

13

0.16

T

111

476

5.78

Ural

11

37

0.45

X

17

56

0.68

Total

190

726

8.81

Unknown

Unknown

786

1301

15.79

Total

1473

8242

100.00

Figure 1

Figure 2:

Figure 3:

Husain Poonawala, MBBS1, Amit Verma, PhD2 and Narender Kumar, PhD2, (1)Immunology, National Institute for Research in Tuberculosis, Chennai, India, (2)Department of Medicine, University of Cambridge, Cambridge, United Kingdom

Disclosures:

H. Poonawala, None

A. Verma, None

N. Kumar, None

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