We have used RNA-RNA in situ hybridization to detect the expression of several Mycobacterium tuberculosis genes in tuberculous granulomas in lung tissue sections from tuberculosis patients. The M. tuberculosis genes chosen fall into two classes. Four genes (icl, narX, and Rv2557 and Rv2558) have been implicated in the persistence of the bacterium in the host, and two genes (iniB and kasA) are upregulated in response to isoniazid exposure. Both necrotic and nonnecrotic granulomas were identified in all of the patients. Necrotic granulomas were divided into three zones: an outer lymphocyte cuff containing lymphocytes and macrophages, a transition zone consisting of necrotic material interspersed with macrophages, and a central acellular necrotic region. Transcripts of all of the genes studied were found in nonnecrotic granulomas and in the lymphocyte cuff of necrotic granulomas. Mycobacterial gene expression was associated with CD68-positive myeloid cells. Rv2557 and/or its homologue Rv2558, kasA, and iniB were expressed within the transition zone of necrotic granulomas, whereas icl and narX transcripts were absent from this area. There was no evidence of transcription of any of the genes examined in the central necrotic region, although mycobacterial DNA was present. The differential expression of genes within granulomas demonstrates that M. tuberculosis exists in a variety of metabolic states and may be indicative of the response to different microenvironments. These observations confirm that genes identified in models of persistence or in response to drug treatment in vitro are expressed in the human host.

Background People who inject drugs (PWID) are at high risk for hepatitis C (HCV), hepatitis B (HBV) and HIV without accessible harm reduction programmes. Coverage of needle and syringe and opioid substitution therapy (OST) services in South Africa is below global recommendations and no hepatitis services exist for PWID. We assessed HCV, HBV and HIV prevalence and risk factors among PWID accessing harm reduction services in Cape Town, Durban and Pretoria to inform policy and programming. Methods We conducted a cross-sectional survey among PWID in these cities between August 2016 and October 2017. Participants were opportunistically sampled while accessing services. Study team members administered a questionnaire that assessed sociodemographic characteristics, drug use and sexual risk practices. We tested for HCV (antibody, viral load and genotype), HBV surface antigen (HBsAg) and HIV. Bivariate and multivariate analyses assessed associations with HCV serostatus. Results Nine hundred and forty-three PWID were included in the per protocol analysis. The majority (87%, 819/943) were male, the overall median age was 29 and most lived on the street (66%, 626/943). At last injection, 77% (722/943) reported using a new needle and syringe and 17% (163/943) shared equipment. HIV prevalence was 21% (196/926), HBsAg positivity 5% (47/936), HCV seroprevalence 55% (513/937), HCV viraemic prevalence (proportion tested with detectable HCV) 43% (404/937) and HCV viraemic rate (proportion HCV antibody positive with detectable HCV) 79% (404/513). HCV genotype 1a (73%, 270/368) was the most prevalent. In multivariate analysis, HCV infection was positively associated with residing in Pretoria (adjusted odds ratio (aOR) 1.27, 95% CI 1.21–1.34), living on the street (aOR 1.90, 95% CI 1.38–2.60), frequent injecting (aOR 1.58, 95% CI 1.15–2.16) and HIV infection (aOR 1.69, 95% CI 1.15–2.47), and negatively associated with black race (aOR 0.52, 95% CI 0.36–0.74) and sexual activity in the previous month (aOR 0.61, 95% CI 0.42–0.88). Conclusions HCV and HIV are major health threats affecting PWID in these cities. Access to OST and needle and syringe services needs to be increased and integrated with HCV services. Social and structural factors affecting PWID who live on the street need to be addressed.

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