Diabetes screen during tuberculosis contact investigations highlights opportunity for new diabetes diagnosis and reveals metabolic differences between ethnic groups

Type 2 diabetes (T2D) is a prevalent risk factor for tuberculosis (TB), but most studies on TB-T2D have focused on TB patients, been limited to one community, and shown a variable impact of T2D on TB risk or treatment outcomes. We conducted a cross-sectional assessment of sociodemographic and metabolic factors in adult TB contacts with T2D (versus no T2D), from the Texas-Mexico border to study Hispanics, and in Cape Town to study South African Coloured ethnicities. The prevalence of T2D was 30.2% in Texas-Mexico and 17.4% in South Africa, with new diagnosis in 34.4% and 43.9%, respectively. Contacts with T2D differed between ethnicities, with higher smoking, hormonal contraceptive use and cholesterol levels in South Africa, and higher obesity in Texas-Mexico (p \u3c 0.05). PCA analysis revealed striking differences between ethnicities in the relationships between factors defining T2D and dyslipidemias. Our findings suggest that screening for new T2D in adult TB contacts is effective to identify new T2D patients at risk for TB. Furthermore, studies aimed at predicting individual TB risk in T2D patients, should take into account the heterogeneity in dyslipidemias that are likely to modify the estimates of TB risk or adverse treatment outcomes that are generally attributed to T2D alone

Diabetes screen during tuberculosis contact investigations highlights opportunity for new diabetes diagnosis and reveals metabolic differences between ethnic groups

Type 2 diabetes (T2D) is a prevalent risk factor for tuberculosis (TB), but most studies on TB-T2D have focused on TB patients, been limited to one community, and shown a variable impact of T2D on TB risk or treatment outcomes. We conducted a cross-sectional assessment of sociodemographic and metabolic factors in adult TB contacts with T2D (versus no T2D), from the Texas-Mexico border to study Hispanics, and in Cape Town to study South African Coloured ethnicities. The prevalence of T2D was 30.2% in Texas-Mexico and 17.4% in South Africa, with new diagnosis in 34.4% and 43.9%, respectively. Contacts with T2D differed between ethnicities, with higher smoking, hormonal contraceptive use and cholesterol levels in South Africa, and higher obesity in Texas-Mexico (p < 0.05). PCA analysis revealed striking differences between ethnicities in the relationships between factors defining T2D and dyslipidemias. Our findings suggest that screening for new T2D in adult TB contacts is effective to identify new T2D patients at risk for TB. Furthermore, studies aimed at predicting individual TB risk in T2D patients, should take into account the heterogeneity in dyslipidemias that are likely to modify the estimates of TB risk or adverse treatment outcomes that are generally attributed to T2D alone

Identification of distinct bio-signatures in whole blood and in-tube quantiferon pellets of Tuberculosis (TB) close contacts (CCs) and TB patients with and without type 2 diabetes (T2D)

Thesis (PhD)--Stellenbosch University, 2019.ENGLISH ABSTRACT: Tuberculosis (TB) remains difficult to control despite effective treatment and the presence of more sensitive diagnostic tools. Immunity against Mycobacterium tuberculosis (Mtb) infection can further be impacted by other concomitant infections (like human immunodeficiency virus) and non-communicable diseases (like Type 2 diabetes (T2D)) rendering individuals susceptible to TB. T2D patients are three times more likely to progress from latent to active TB.Therefore, it is crucial to better understand why people with T2D are at increased risk for TB progression. We hypothesize that distinct bio-signatures exist in whole blood of TB patients and close contacts (CCs) of TB patients with latent TB infection (LTBI) with T2D compared to those without T2D and that these bio-signatures correlate with impaired immune responses to Mtb in peripheral blood mononuclear cells (PBMCs) and monocytes (MNs) in CCs. RNA was extracted from whole blood stimulated with Mtb antigens using the Quantiferon TB Gold in-tube assay and NanoString analysis was performed to determine whether specific transcription signatures exist between CCs with LTBI with and without T2D. We characterized serum cytokines and endocrine signatures by luminex and enzyme-linked immunosorbent assay. PBMCs and MNs from the same individuals were isolated and stimulated with live H37Rv Mtb to determine Mtb uptake and killing. Bacterial uptake and killing was correlated with HbA1c to determine whether there was an association with glycaemic control. RNA from TB patients, TB patients with transient hyperglycaemia (TB-THG) and TB patients with T2D (TB-T2D) was also extracted from whole blood stimulated with Mtb antigens and analysed using NanoString. Interleukin-22 was also measured in serum from these patients. PBMCs from TB patients were further used to determine the frequency of mucosal associated invariant T (MAIT) cells before, during and after TB treatment. Fifteen gene transcripts were downregulated in TB-T2D compared to TB and TB-THG patients. We identified a gene signature that was able to differentiate between TB-THG and TB-T2D. We further identified a gene signature unique to the CCs with LTBI and T2D, which could be associated with an increased risk of developing active TB. Differences in cytokines, hormones, lipids, differential blood counts and Mtb uptake was observed when comparing CCs with and without T2D. Differential expression of IL-6, IL-18 and IL-22 in CCs with and without T2D highlights the differential regulation of the immune response during T2D. We showed that the frequency of MAIT cells in the periphery of TB-T2D was significantly lower compared to TB-THG at baseline, suggesting the MAIT cells in TB-T2D have redistributed to either the lung or adipose tissue. The increase of MAIT cells in the periphery at month 2 compared to baseline could mean that MAIT cells population was restored in the blood due to TB treatment. Our gene expression results suggests that downregulated gene transcripts may be involved in pathways that favour immunopathology in TB-T2D. In addition, gene signatures differentiating THG from T2D could be useful in preventing the unnecessary diagnosis of patients with THG as having T2D. Differential gene expression in CCs with LTBI with and without T2D shows potential to be involved in the mechanisms leading to susceptibility to active TB. Cytokine and hormone data confirms that during T2D, the immune response is differentially regulated which may influence the response to infections. Lastly, MAIT cell frequency could be useful for monitoring treatment responses in TB-T2D patients.AFRIKAANSE OPSOMMING: Tuberkulose (TB) bly moeilik om te beheer ten spyte van effektiewe behandeling en die teenwoordigheid van meer sensitiewe diagnostiese toetse. Immuniteit teen Mycobacterium tuberkulose (Mtb) kan verder beïnvloed word deur ander gepaardgaande infeksies (soos menslike immuniteitsgebrekvirus) en nie-oordraagbare siektes (soos tipe 2 diabetes (T2D)) wat individue vatbaar maak vir TB. Pasiënte met T2D het ʼn groter kans om van latent na aktiewe TB te vorder en is dit noodsaaklik om te verstaan waarom mense met T2D ‘n groter risiko vir TB-progressie het. Ons veronderstel dat daar afsonderlike bio-handtekeninge in heel bloed van TB pasiënte asook nabye kontakte (CCs) van TB pasiënte met latente TB-infeksie (LTBI) en T2D in vergelyking met dié sonder T2D bestaan en dat hierdie bio-handtekeninge met verswakte immuunresponse teenoor Mtb in mononukleêr selle in perifere bloed (PBMCs) en monosiete (MNs) van CCs korreleer. RNS is uit volbloed wat met Mtb-antigene (Quantiferon TB Gold toets) gestimuleer is onttrek. Nanostring-analise is uitgevoer om vas te stel of spesifieke transkripsie-patrone tussen CCs met LTBI en met of sonder T2D bestaan. Ons het serum sitokiene en endokriene handtekeninge identifiseer deur luminex en ensien-gekoppelde Immunosorbent-toetse. PBMCs en MNs van dieselfde individue is geïsoleer en met lewendige H37Rv Mtb gestimuleer om Mtb opname en beheer te bepaal. Bakteriese opname en dood was met HbA1c gekorreleer om vas te stel of daar 'n verband met bloedsuiker was. RNS van TB-pasiënte, TB-pasiënte met oorgang hiperglukemie (TB-THG) en TB-pasiënte met T2D (TB-T2D) was ook uit heelbloed wat met Mtb-antigene gestimuleers was onttrek en met behulp van die Nanostring tegnologie geanaliseer. IL-22 was ook in the serum van hierdie pasiënte gemeet. PBMCs van TB pasiënte is verder gebruik om die frekwensie van ‘mucosal associated invariant’ T (MAIT) selle voor, tydens en na TB behandeling te bepaal.Vyftien geen-transkripsies is in TB-T2D afwaarts gereguleer in vergelyking met TB- en TB-THG pasiënte. Ons het 'n geen-handtekening geïdentifiseer wat in staat was om tussen TB-THG en TB-T2D te onderskei. Ons het verder 'n handtekening van gene geïdentifiseer wat uniek is aan die CCs met LTBI en T2D wat met 'n verhoogde risiko om aktiewe TB te ontwikkeling geassosieer kan word. Verskille in sitokiene, hormone, lipiede, differensiële bloedtellings en Mtb opname is waargeneem tydens die vergelyking van CC's met en sonder T2D. Differensiële uitdrukking van IL-6, IL-18 en IL-22 in CCs met LTBI met en sonder T2D beklemtoon die differensiële regulering van die immuunrespons tydens T2D. Ons het getoon dat die frekwensie van MAIT selle in die sirkulasie van TB-T2D laer was as TB-THG by basislyn, wat daarop dui dat die MAIT-selle in TB-T2D na die long- of vetweefsel migreer. Die toename van MAIT selle in die bloed by maand 2 in vergelyking met basislyn kan beteken dat MAIT selpopulasies in die bloed herstel, as gevolg van TB behandeling.Doctora

Extract from used Xpert MTB/ RIF Ultra cartridges is useful for accurate second-line drug-resistant tuberculosis diagnosis with minimal rpoB-amplicon cross-contamination risk

CITATION: Venter, R., et al. 2020. Extract from used Xpert MTB/ RIF Ultra cartridges is useful for accurate second-line drug-resistant tuberculosis diagnosis with minimal rpoB-amplicon cross-contamination risk. Scientific Reports, 10:2633, doi:10.1038/s41598-020-59164-3.The original publication is available at https://www.nature.comPublication of this article was funded by the Stellenbosch University Open Access Fund.Xpert MTB/RIF Ultra (Ultra) detects Mycobacterium tuberculosis and rifampicin resistance. Follow-on drug susceptibility testing (DST) requires additional sputum. Extract from the diamond-shaped chamber of the cartridge (dCE) of Ultra’s predecessor, Xpert MTB/RIF (Xpert), is useful for MTBDRsl-based DST but this is unexplored with Ultra. Furthermore, whether CE from non-diamond compartments is useful, the performance of FluoroType MTBDR (FT) on  CE, and rpoB cross-contamination risk associated with the extraction procedure are unknown. We tested MTBDRsl, MTBDRplus, and FT on CEs from chambers from cartridges (Ultra, Xpert) tested on bacilli dilution series. MTBDRsl on Ultra dCE on TB-positive sputa (n = 40) was also evaluated and, separately, rpoB amplicon cross-contamination risk . MTBDRsl on Ultra dCE from dilutions ≥103 CFU/ml (CTmin “low semi-quantitation”) detected fluoroquinolone (FQ) and second-line injectable (SLID) susceptibility and resistance correctly (some SLIDs-indeterminate). At the same threshold (at which ~85% of Ultra-positives in our setting would be eligible), 35/35 (100%) FQ and 34/35 (97%) SLID results from Ultra dCE were concordant with sputa results. Tests on other chambers were unfeasible. No tubes open during 20 batched extractions had FT-detected rpoB cross-contamination. False-positive Ultra rpoB results was observed when dCE dilutions ≤10−3 were re-tested. MTBDRsl on Ultra dCE is concordant with isolate results. rpoB amplicon cross-contamination is unlikely. These data mitigate additional specimen collection for second-line DST and cross-contamination concerns.https://www.nature.com/articles/s41598-020-59164-3Publisher's versio

GPR183 regulates interferons, autophagy, and bacterial growth during Mycobacterium tuberculosis&nbsp;infection and is associated with TB disease severity

Oxidized cholesterols have emerged as important signaling molecules of immune function, but little is known about the role of these oxysterols during mycobacterial infections. We found that expression of the oxysterol-receptor GPR183 was reduced in blood from patients with tuberculosis (TB) and type 2 diabetes (T2D) compared to TB patients without T2D and was associated with TB disease severity on chest x-ray. GPR183 activation by 7α,25-dihydroxycholesterol (7α,25-OHC) reduced growth of\ua0Mycobacterium tuberculosis\ua0(Mtb) and\ua0Mycobacterium bovis\ua0BCG in primary human monocytes, an effect abrogated by the GPR183 antagonist GSK682753. Growth inhibition was associated with reduced IFN-β and IL-10 expression and enhanced autophagy. Mice lacking GPR183 had significantly increased lung Mtb burden and dysregulated IFNs during early infection. Together, our data demonstrate that GPR183 is an important regulator of intracellular mycobacterial growth and interferons during mycobacterial infection