People who use illicit drugs (PWUDs) have been identified as a key at-risk group for tuberculosis (TB). Examination of illicit drug use networks has potential to assess the risk of TB exposure and disease progression. Research also is needed to assess mechanisms for accelerated TB transmission in this population. This study aims to 1) assess the rate of TB exposure, risk of disease progression, and disease burden among PWUD; 2) estimate the proportion of active TB cases resulting from recent transmission within this network; and 3) evaluate whether PWUD with TB disease have physiologic characteristics associated with more efficient TB transmission. Our cross-sectional, observational study aims to assess TB transmission through illicit drug use networks, focusing on methamphetamine and Mandrax (methaqualone) use, in a high TB burden setting and identify mechanisms underlying accelerated transmission. We will recruit and enroll 750 PWUD (living with and without HIV) through respondent driven sampling in Worcester, South Africa. Drug use will be measured through self-report and biological measures, with sputum specimens collected to identify TB disease by Xpert Ultra (Cepheid) and mycobacterial culture. We will co-enroll those with microbiologic evidence of TB disease in Aim 2 for molecular and social network study. Whole genome sequencing of Mycobacteria tuberculosis (Mtb) specimens and social contact surveys will be done for those diagnosed with TB. For Aim 3, aerosolized Mtb will be compared in individuals with newly diagnosed TB who do and do not smoke illicit drug. Knowledge from this study will provide the basis for a strategy to interrupt TB transmission in PWUD and provide insight into how this fuels overall community transmission. Results have potential for informing interventions to reduce TB spread applicable to high TB and HIV burden settings. Trial registration: Clinicaltrials.gov Registration Number: NCT041515602. Date of Registration: 5 November 2019.

Sputum cultures are the gold standard for tuberculosis (TB) diagnosis and treatment monitoring. However, cultures in MGIT liquid media are susceptible to microbial contamination, often rendering them uninterpretable. Research has shown that maintaining strict cold chains and supervised sample collection can reduce contamination rates, but few longitudinal studies with weekly sampling have explored this. Here, we evaluated whether (i) the time between specimen collection and laboratory processing and (ii) unsupervised specimen collection are associated with contamination rates. Additionally, we estimated contamination rates over the first 12 weeks of treatment and assessed the clinical and behavioral predictors of contamination. We collected 3,155 sputum specimens from 301 participants undergoing TB treatment. Contamination was lowest (12.3%) at treatment initiation, increased over the first few weeks, and stabilized around 30% from week 8 onwards. Samples collected without supervision were more likely to be contaminated at treatment initiation ( P = 0.048) and over 12 weeks ( P = 0.028). We observed an inverse relationship between smear grade and contamination risk throughout the sampling period. These findings underscore the importance of supervised sputum collection to reduce contamination and provide ways to enhance the clinical and research values of weekly cultures, particularly those collected later in treatment. This is especially relevant for community-collected specimens used in monitoring treatment response. IMPORTANCE: It is essential to understand how we can minimize sputum specimen contamination rates, as culture contamination may lead to false negative or indeterminate results that require repeat sampling and testing, increasing the burden on healthcare systems and potentially delaying treatment initiation. This research underscores the importance of maintaining a stringent cold chain and highlights the need for participant education and supervision during sample collection. The findings from this study have important implications for TB diagnosis and treatment outcome programs in low- and middle-income countries where biosafety level 3 facilities are located within centralized national reference laboratories or tertiary care hospitals.

The Western Cape is South Africa’s epicentre for tuberculosis (TB) and smoked drug use such as methamphetamine and methaqualone (Mandrax). Despite this, there are limited studies on people who smoke drugs (PWSD) with TB disease in South Africa, partly due to recruitment challenges. Respondent-driven sampling (RDS) is a network-based sampling method used to recruit such key populations. The aim of this qualitative study is to explore the appropriateness and feasibility of RDS as a method for recruiting PWSD for a planned study on TB transmission in this setting. We conducted ten focus group discussions (n = 84) with men and women from Worcester, a rural town in the Western Cape, who self-reported current methamphetamine and/or methaqualone use. Participants were recruited through an existing TB study or community-based outreach. Discussion topics included use of illicit drugs within social networks, feasibility of using RDS methods for recruiting PWSD, and logistical recommendations for the use of RDS and planned study participation. Data were analyzed using thematic analysis. Results indicate drug use by participants across large social networks which is favorable for RDS methods. The key themes were: 1) drug-use social network characteristics including demographic and geographic differences; 2) perspectives of PWSD on RDS methods; 3) potential challenges to proposed RDS recruitment and participation in a larger research study for PWSD, and 4) participant recommendations to enhance the uptake of RDS and study participation by PWSD. RDS seems to be a feasible method to recruit PWSD and improve the possibility of reaching a diverse sample of PWSD, with clear recommendations from participants regarding how to recruit participants for larger research studies. The current study indicates that conducting formative, qualitative research can assist researchers with RDS study design and planning for additional study activities. Trial Registration: ClinicalTrials.gov NCT041515602

Stigma acts as a barrier to the diagnosis and effective treatment of tuberculosis (TB). Individuals with TB who also use alcohol or drugs (AODs), including methamphetamine, may experience intersectional stigma. Further, the nature and intensity of these intersecting stigmas may be compounded by co-morbidities like HIV and marginalized social status. Despite this, AOD use stigma has rarely been studied in the context of TB and other co-occurring conditions. We examined the perceptions and experiences of AOD use-related stigma among individuals who were previously diagnosed with TB or were at increased risk of TB based on their close contacts, in a rural community in the Western Cape, South Africa. We analyzed qualitative data collected by two studies (study 1: five focus groups (n=34), study 2: ten focus groups (n=84)). Findings highlighted that study participants who use AODs experienced intersectional stigma from multiple sources. AOD use- and TB-related stigma were experienced from friends, family, healthcare providers, and the broader community, particularly for those who used illicit drugs. Participants discussed stigma’s effects on their health and well-being. The negative effects of AOD use stigma were particularly salient among female participants. Findings indicate that intersecting stigmas exist at multiple levels for people who use AODs with/at risk of TB, and that these stigmas hinder healthcare utilization in this rural setting. Future interventions to improve TB service uptake need to address intersectional AOD use and TB stigma.

Background: Tuberculosis (TB) transmission is heterogenous, yet high-risk populations remain poorly defined. We aimed to assess whether people who smoke drugs (PWSD) have elevated TB disease rates in a high-burden setting. Methods: We recruited PWSD from a rural community in the Western Cape, South Africa, using respondent-driven sampling (RDS). Participants were ≥15 years old, tested positive for methamphetamine and/or methaqualone, and completed TB and HIV testing and biobehavioral surveys. We defined TB disease as culturable TB, Xpert MTB/RIF Ultra (Ultra) MTB detected with no history of TB, Ultra traceamong persons with HIV (PWH) >2 years from any prior diagnosis, or currently on TB treatment. We summarized population-level characteristics and estimated TB prevalence using the RDS-II estimator. We identified characteristics associated with TB using logistic regression. Results: Between April 2021 and October 2023, we enrolled 750 PWSD. Overall, 71.5% (95% CI, 66.1%–76.8%) were male and the mean age was 34 years (95% CI, 33%–36%); 17.5% (95% CI, 13.0%–22.0%) were PWH, of whom 31.6% were newly diagnosed. RDS-adjusted TB prevalence was 10.4% (95% CI, 6.5%–14.3%). TB prevalence among PWSD without HIV was 8.1% (95% CI, 4.4%–11.9%), compared to 20.9% (95% CI, 8.4%–33.4%) with HIV. PWH had 3.3-fold greater adjusted odds of having TB disease (95% CI, 1.9%–5.8%). Conclusions: PWSD identified through RDS had substantially elevated TB and HIV rates, with 20% of PWSD with HIV having TB. We successfully engaged PWSD in TB screening using peer recruitment. These findings highlight opportunities for community transmission identification and interventions.

Sputum cultures are the gold standard for tuberculosis (TB) diagnosis and treatment monitoring. However, cultures in MGIT liquid media are susceptible to microbial contamination, often rendering them uninterpretable. Research has shown that maintaining strict cold chains and supervised sample collection can reduce contamination rates, but few longitudinal studies with weekly sampling have explored this. Here we evaluated whether (1) the time between specimen collection and laboratory processing and (2) unsupervised specimen collection are associated with contamination rates. Additionally, we estimated contamination rates over the first 12 weeks of treatment and assessed clinical and behavioral predictors of contamination. We collected 3155 sputum specimens from 301 participants undergoing TB treatment. Contamination was lowest (12.3%) at treatment initiation, increased over the first few weeks, and stabilized around 30% from week 8 onwards. Samples collected without supervision were more likely to be contaminated at treatment initiation (p=0.048) and over the 12 weeks (p=0.028). We observed an inverse relationship between smear grade and contamination risk throughout the sampling period. These findings underscore the importance of supervised sputum collection to reduce contamination and provide ways to enhance the clinical and research value of weekly cultures, particularly those collected later in treatment. This is especially relevant for community-collected specimens used in monitoring treatment response.