1397. Modern Lineages of Mycobacterium tuberculosis Were Recently Introduced in Western India and Demonstrate Increased Transmissibility

Abstract Background Mycobacterium tuberculosis (Mtb) transmissibility may vary between lineages (or variants) and this may contribute to the slow decline of tuberculosis incidence. The objective of our study was to compare transmissibility across four major lineages (L1-4) of Mtb in Pune, India. Methods We performed whole-genome sequencing (WGS) of Mtb isolated from sputum culture of adult patients with pulmonary TB. We performed genotypic susceptibility testing for both first- and second-line drugs using a previously validated random forest predictor. We identified single nucleotide polymorphisms and generated a multiple sequence alignment excluding drug resistance conferring mutations to avoid skewing the phylogeny due to convergent evolution in these regions. We used Bayesian molecular dating to generate phylogenies and compared tree characteristics using a two-sample Kolmogorov-Smirnov (KS) test. Results Of the 642 isolates from distinct study participants that underwent WGS, 612 met quality criteria. The median age of participants was 31 years (range 18-74), the majority were male (64.7%) and sputum smear-positive (83.3%), and 6.7% had co-infection with HIV (Table 1). There was no significant difference in baseline characteristics between lineages. The majority of isolates belonged to L3 (44.6%). The majority (61.1%) of multidrug-resistant (MDR, resistant to isoniazid and rifampin) isolates belonged to L2. In phylogenetic analysis, we found evidence of higher transmissibility of L2 as indicated by shorter branch lengths (i.e., less time had elapsed between transmission and sampling) and more genetic similarity (smaller pairwise single nucleotide polymorphism [SNP] distances) among L2 isolates as compared to other lineages (Figure 1). Branching times for L2 and L4 were smaller than L1 and L3 indicating recent introduction into the region (p < 0.001 [KS test]). Figure 1: Lineage-wise distribution of A) phylogenetic tree branch lengths (log) and B) pairwise single nucleotide polymorphism (SNP) distance, using 612 tuberculosis isolates from Pune, India. P values calculated using two-sample Kolmogorov-Smirnov test. Table 1: Demographic characteristics of study participants included in the study, by lineage. Conclusion Modern Mtb lineages (L2 and L4) were relatively recently introduced in western India, as compared to older lineages (L1 and L3), with the more drug-resistant L2 showing higher transmissibility. These findings highlight the need for early detection and treatment initiation to interrupt transmission with important implications for antimicrobial stewardship and heightened surveillance of TB resistance rates. Disclosures All Authors: No reported disclosures


The Incremental Hospitalization Burden Associated with Nontuberculous
Background. NTMLD is a life-threatening pulmonary infection with increasing incidence and prevalence in Japan. It is associated with progressive lung damage and increased healthcare use. Many patients with NTMLD have comorbid respiratory conditions such as COPD. Treatment of NTMLD in patients with COPD is difficult, however there is limited data on the incremental burden that NTMLD adds to underlying COPD. We assessed the incremental burden associated with NTMLD in Japanese patients with COPD by comparing their hospitalizations to matched COPD patients without NTMLD.
Methods. A retrospective cohort study was conducted using claims data provided by the Japan Medical Data Center (2015-2020). COPD patients with NTMLD were matched 1:3 to COPD patients without NTMLD (controls). Hospitalizations (allcause, respiratory-related, and COPD-related) were accrued over a 1-year follow-up period after NTMLD diagnosis (index). Incremental burden of NTMLD was assessed by comparing hospitalizations between COPD patients with NTMLD and controls with univariate and multivariate analyses adjusting for comorbidities during 1-year pre-index period.
Results. A total of 492 COPD patients with NTMLD were matched by age and sex to 1476 controls. Mean (SD) age on index date was 56.6 (10.3) years and 61.4% were females. Compared to controls, NTMLD patients had higher prevalence of some pulmonary symptoms and comorbidities such as hemoptysis (11% vs 2%), dyspnea (1.6% vs 0.6%) and lung cancer (7% vs 4%). In univariate analyses, a higher percent of COPD patients with NTMLD had hospitalizations compared to controls ( Fig 1A); the unadjusted annual hospitalization rates were also higher among patients with NTMLD (Fig 2A). Multivariate regressions after adjusting for pre-index comorbidities showed COPD patients with NTMLD were 1.9 times more likely to have an all-cause hospitalization, 2.8 times more likely to have a respiratory hospitalization, and 3.0 times more likely to have a COPD-related hospitalization (Fig 1B).
Conclusion. COPD patients with NTMLD had a higher burden of hospitalization than COPD patients without NTMLD. The statistically significantly incremental burden associated with NTMLD in patients with COPD highlights the acute need for appropriate management of NTMLD in Japan. Background. Mycobacterium tuberculosis (Mtb) transmissibility may vary between lineages (or variants) and this may contribute to the slow decline of tuberculosis incidence. The objective of our study was to compare transmissibility across four major lineages (L1-4) of Mtb in Pune, India.

Disclosures. Naoki Hasegawa
Methods. We performed whole-genome sequencing (WGS) of Mtb isolated from sputum culture of adult patients with pulmonary TB. We performed genotypic susceptibility testing for both first-and second-line drugs using a previously validated random forest predictor. We identified single nucleotide polymorphisms and generated a multiple sequence alignment excluding drug resistance conferring mutations to avoid skewing the phylogeny due to convergent evolution in these regions. We used Bayesian molecular dating to generate phylogenies and compared tree characteristics using a two-sample Kolmogorov-Smirnov (KS) test.
Results. Of the 642 isolates from distinct study participants that underwent WGS, 612 met quality criteria. The median age of participants was 31 years (range 18-74), the majority were male (64.7%) and sputum smear-positive (83.3%), and 6.7% had co-infection with HIV (Table 1). There was no significant difference in baseline characteristics between lineages. The majority of isolates belonged to L3 (44.6%). The majority (61.1%) of multidrug-resistant (MDR, resistant to isoniazid and rifampin) isolates belonged to L2. In phylogenetic analysis, we found evidence of higher transmissibility of L2 as indicated by shorter branch lengths (i.e., less time had elapsed between transmission and sampling) and more genetic similarity (smaller pairwise single nucleotide polymorphism [SNP] distances) among L2 isolates as compared to other lineages ( Figure 1). Branching times for L2 and L4 were smaller than L1 and L3 indicating recent introduction into the region (p < 0.001 [KS test]). Figure 1: Lineage-wise distribution of A) phylogenetic tree branch lengths (log) and B) pairwise single nucleotide polymorphism (SNP) distance, using 612 tuberculosis isolates from Pune, India. P values calculated using two-sample Kolmogorov-Smirnov test. Table 1: Demographic characteristics of study participants included in the study, by lineage.
Conclusion. Modern Mtb lineages (L2 and L4) were relatively recently introduced in western India, as compared to older lineages (L1 and L3), with the more drug-resistant L2 showing higher transmissibility. These findings highlight the need for early detection and treatment initiation to interrupt transmission with important implications for antimicrobial stewardship and heightened surveillance of TB resistance rates.
Disclosures. All Authors: No reported disclosures