Browsing by Subject "drugs"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Open Access
    Reducing substance use and sexual risk behaviour among men who have sex with men in South Africa
    (2016) Parry, Charles DH
    Abstract Men who have sex with men have been identified as a population at risk of acquiring and transmitting HIV. Studies in South Africa have reported a high prevalence of HIV, as well as high levels of alcohol and other drug use, among men who have sex with men, and the use of substances (alcohol and drugs) to facilitate their sexual encounters. Since 2007, interventions focused on prevention have been rolled out to vulnerable men who have sex with men and who also use alcohol or other drugs. The interventions include community-based outreach; provision of information on HIV/AIDS, substance abuse, and safer sex practices; and the development of risk-reduction plans. Among 195 men who participated in our study, there were significant reductions in the proportion who used cannabis and ecstasy, including the use of these drugs during sex. No reduction was observed in the use of any other substances. In general, after the intervention our participants reported less frequent use of alcohol and drugs and greater engagement in safer sexual practices. Despite these encouraging findings, the combination of substance use while engaging in sex had actually increased. The study findings suggest that interventions that target men who have sex with men, and who use alcohol and other drugs, could reduce risk behaviours in this population.
  • Thumbnail Image
    Item
    Open Access
    The within-host population dynamics of Mycobacterium tuberculosis vary with treatment efficacy
    (2017) Trauner, Andrej; Liu, Qingyun; Via, Laura E; Liu, Xin; Ruan, Xianglin; Liang, Lili; Shi, Huimin; Chen, Ying; Wang, Ziling; Liang, Ruixia; Zhang, Wei; Wei, Wang; Gao, Jingcai; Sun, Gang; Brites, Daniela; England, Kathleen; Zhang, Guolong; Gagneux, Sébastien; Barry, Clifton E; Gao, Qian
    BACKGROUND: Combination therapy is one of the most effective tools for limiting the emergence of drug resistance in pathogens. Despite the widespread adoption of combination therapy across diseases, drug resistance rates continue to rise, leading to failing treatment regimens. The mechanisms underlying treatment failure are well studied, but the processes governing successful combination therapy are poorly understood. We address this question by studying the population dynamics of Mycobacterium tuberculosis within tuberculosis patients undergoing treatment with different combinations of antibiotics. RESULTS: By combining very deep whole genome sequencing (~1000-fold genome-wide coverage) with sequential sputum sampling, we were able to detect transient genetic diversity driven by the apparently continuous turnover of minor alleles, which could serve as the source of drug-resistant bacteria. However, we report that treatment efficacy has a clear impact on the population dynamics: sufficient drug pressure bears a clear signature of purifying selection leading to apparent genetic stability. In contrast, M. tuberculosis populations subject to less drug pressure show markedly different dynamics, including cases of acquisition of additional drug resistance. CONCLUSIONS: Our findings show that for a pathogen like M. tuberculosis, which is well adapted to the human host, purifying selection constrains the evolutionary trajectory to resistance in effectively treated individuals. Nonetheless, we also report a continuous turnover of minor variants, which could give rise to the emergence of drug resistance in cases of drug pressure weakening. Monitoring bacterial population dynamics could therefore provide an informative metric for assessing the efficacy of novel drug combinations.