Association between bacterial homoplastic variants and radiological pathology in tuberculosis.

BACKGROUND: Understanding how pathogen genetic factors contribute to pathology in TB could enable tailored treatments to the most pathogenic and infectious strains. New strategies are needed to control drug-resistant TB, which requires longer and costlier treatment. We hypothesised that the severity of radiological pathology on the chest radiograph in TB disease was associated with variants arising independently, multiple times (homoplasies) in the Mycobacterium tuberculosis genome. METHODS: We performed whole genome sequencing (Illumina HiSeq2000 platform) on M. tuberculosis isolates from 103 patients with drug-resistant TB in Lima between 2010 and 2013. Variables including age, sex, HIV status, previous TB disease and the percentage of lung involvement on the pretreatment chest radiograph were collected from health posts of the national TB programme. Genomic variants were identified using standard pipelines. RESULTS: Two mutations were significantly associated with more widespread radiological pathology in a multivariable regression model controlling for confounding variables (Rv2828c.141, RR 1.3, 95% CI 1.21 to 1.39, p<0.01; rpoC.1040 95% CI 1.77 to 2.16, RR 1.9, p<0.01). The rpoB.450 mutation was associated with less extensive radiological pathology (RR 0.81, 95% CI 0.69 to 0.94, p=0.03), suggestive of a bacterial fitness cost for this mutation in vivo. Patients with a previous episode of TB disease and those between 10 and 30 years of age also had significantly increased radiological pathology. CONCLUSIONS: This study is the first to compare the M. tuberculosis genome to radiological pathology on the chest radiograph. We identified two variants significantly positively associated with more widespread radiological pathology and one with reduced pathology. Prospective studies are warranted to determine whether mutations associated with increased pathology also predict the spread of drug-resistant TB.

Tuberculosis case notifications and outcomes in Peruvian prisons prior to and during the COVID-19 pandemic: a national-level interrupted time series analysis.

Background: The COVID-19 pandemic has significantly disrupted tuberculosis (TB) programs, making it urgent to focus TB elimination efforts on key populations. People experiencing incarceration are at high risk for TB, however, how COVID-19-related disruptions have impacted incarcerated populations with TB is unknown. Methods: Using Peruvian National TB Program data from Jan 2018 to Dec 2021, an interrupted time series of drug-susceptible (DS) TB case notifications pre- and during COVID-19 was conducted (cut-off date: COVID-19 emergency declaration in Peru, 16 March 2020). The effect of TB care occurring pre-vs. during COVID-19 on TB treatment success in the incarcerated and non-incarcerated populations was explored using logistic regression. Findings: DS-TB cases notified in prisons from Jan 2018 to Dec 2021 (n = 10,134) represented 10% of all cases notified in the country (n = 101,507). In the first week of COVID-19, DS-TB case notifications dropped by 61.2% (95% CI: 59.9-62.7%) in the non-incarcerated population and 17.7% (95% CI: 17.5-17.9%) among the incarcerated population. TB treatment success was significantly lower in people receiving TB care entirely during the COVID-19 pandemic vs. before COVID-19 in the non-incarcerated population (OR: 0.81, 95% CI: 0.78-0.85), but not statistically significantly lower in the incarcerated population (OR: 0.88, 95% CI: 0.76-1.01). Incarceration status was not found to modify the effect of COVID-19 period on TB treatment outcomes (OR: 1.07, 95% CI: 0.92-1.25), although treatment success was higher in the incarcerated population (OR [incarcerated vs. not incarcerated, pre-COVID]: 1.52, 95% CI: 1.39-1.67). Interpretation: Both incarcerated and non-incarcerated populations experienced a large drop in DS-TB case notifications (although higher in the non-incarcerated population). Lower TB treatment success among those receiving care during COVID-19 indicates significant TB service disruptions in the overall population. The finding that incarceration at time of diagnosis was associated with treatment success is plausible in Peru given increased screening and stricter treatment monitoring in prisons. Funding: Canadian Institutes of Health Research (Funding Reference Number: 179418) .

Genomic signatures of pre-resistance in Mycobacterium tuberculosis.

Recent advances in bacterial whole-genome sequencing have resulted in a comprehensive catalog of antibiotic resistance genomic signatures in Mycobacterium tuberculosis. With a view to pre-empt the emergence of resistance, we hypothesized that pre-existing polymorphisms in susceptible genotypes (pre-resistance mutations) could increase the risk of becoming resistant in the future. We sequenced whole genomes from 3135 isolates sampled over a 17-year period. After reconstructing ancestral genomes on time-calibrated phylogenetic trees, we developed and applied a genome-wide survival analysis to determine the hazard of resistance acquisition. We demonstrate that M. tuberculosis lineage 2 has a higher risk of acquiring resistance than lineage 4, and estimate a higher hazard of rifampicin resistance evolution following isoniazid mono-resistance. Furthermore, we describe loci and genomic polymorphisms associated with a higher risk of resistance acquisition. Identifying markers of future antibiotic resistance could enable targeted therapy to prevent resistance emergence in M. tuberculosis and other pathogens.