Usability and acceptability of oral fluid- and blood-based hepatitis C virus self-testing among the general population and men who have sex with men in Malaysia.

Hepatitis C self-testing (HCVST) is emerging as an additional strategy that could help to expand access to HCV testing. We conducted a study to assess the usability and acceptability of two types of HCVST, oral fluid- and blood-based, among the general population and men who have sex with men (MSM) in Malaysia. An observational study was conducted in three primary care centres in Malaysia. Participants who were layman users performed the oral fluid- and blood-based HCVST sequentially. Usability was assessed by calculating the rate of errors observed, the rate of difficulties faced by participants as well as inter-reader (self-test interpreted by self-tester vs interpreted by trained user) and inter-operator concordances (self-test vs test performed by trained user). The acceptability of HCV self-testing was assessed using an interviewer-administered semi-structured questionnaire. Participants were also required to read contrived test results which included "positive", "negative", and "invalid". There was a total of 200 participants (100 general population, 100 MSM; mean age 33.6 ± 14.0 years). We found a high acceptability of oral fluid- and blood-based HCVST across both general population and MSM. User errors, related to timekeeping and reading within stipulated time, were common. However, the majority of the participants were still able to obtain and interpret results correctly, including that of contrived results, although there was substantial difficulty interpreting weak positive results. The high acceptability of HCVST among the participants did not appreciably change after they had experienced both tests, with 97.0% of all participants indicating they would be willing to use HCVST again and 98.5% of them indicating they would recommend it to people they knew. There was no significant difference between the general population and MSM in these aspects. Our study demonstrates that both oral fluid- and blood-based HCVST are highly acceptable among both the general population and MSM. Both populations also showed comparable ability to conduct the tests and interpret the results. Overall, this study suggests that HCVST could be introduced as an addition to existing HCV testing services in Malaysia. Further studies are needed to establish the optimal positioning of self-testing alongside facility-based testing to expand access to HCV diagnosis in the country.

Assessing feasibility of a modified same-day test-and-treat model for hepatitis C among rural people who inject drugs.

BACKGROUND: Despite advancements in hepatitis C virus (HCV) treatment, low uptake among hard-to-reach populations remains a global issue. The current study aimed to assess the feasibility of a modified same-day test-and-treat model in improving HCV care for people who inject drugs (PWID) living in resource-constrained rural areas. METHODS: A pilot study was conducted in four primary healthcare (PHC) centers in Malaysia. The model's key features included on-site HCV ribonucleic acid (RNA) testing using a shared GeneXpert® system; noninvasive biomarkers for cirrhosis diagnosis; and extended care to PWID referred from nearby PHC centers and outreach programs. The feasibility assessment focused on three aspects of the model: demand (i.e., uptake of HCV RNA testing and treatment), implementation (i.e., achievement of each step in the HCV care cascade), and practicality (i.e., ability to identify PWID with HCV and expedite treatment initiation despite resource constraints). RESULTS: A total of 199 anti-HCV-positive PWID were recruited. They demonstrated high demand for HCV care, with a 100% uptake of HCV RNA testing and 97.4% uptake of direct-acting antiviral treatment. The rates of HCV RNA positivity (78.4%) and sustained virologic response (92.2%) were comparable to standard practice, indicating the successful implementation of the model. The model was also practical, as it covered non-opioid-substitution-therapy-receiving individuals and enabled same-day treatment in 71.1% of the participants. CONCLUSIONS: The modified same-day test-and-treat model is feasible in improving HCV care for rural PWID. The study finding suggests its potential for wider adoption in HCV care for hard-to-reach populations.

Diagnostic performance of two non-invasive biomarkers used individually and in sequential combination for cirrhosis associated with hepatitis C virus infection.

This cross-sectional study evaluated the performance of the Aspartate Aminotransferase-to-Platelet Ratio Index (APRI) and the Fibrosis-4 (FIB-4) Index when they were used individually and in sequential combination to diagnose cirrhosis associated with hepatitis C virus infection. The final evaluation involved 906 people living with hepatitis C. The diagnostic performance of individual biomarkers at cut-off scores of 1.5 and 2.0 for the APRI and at 3.25 for the FIB-4 index was assessed. For the sequential combination method, the cirrhosis status of individuals with an APRI score between 1.0 and 1.5 were reassessed using the FIB-4. Transient elastography (TE) was used as the reference standard for diagnosing cirrhosis. The APRI, at a cut-off score of 1.5, showed a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 44.9%, 97.6%, 91.1% and 76.3%, respectively. Increasing the cut-off score to 2.0 produced a much lower sensitivity (29.6%) and NPV (71.9%). The FIB-4, at a cut-off score of 3.25, yielded a sensitivity, specificity, PPV and NPV of 40.8%, 97.3%, 89.1% and 75.0%, respectively. The sequential combination method demonstrated a much more optimal diagnostic performance (50.2% sensitivity, 96.6% specificity, 89.0% PPV and 77.9% NPV). Overall, the APRI and FIB-4 Index performed better in diagnosing cirrhosis associated with hepatitis C when they were used in sequential combination.

A quasi-randomised controlled trial of online distribution of home-based hepatitis C self-testing for key populations in Malaysia: a study protocol.

BACKGROUND: Malaysia has an estimated hepatitis C virus (HCV) prevalence of 1.9% among its adult population and a history of providing HCV treatment in the public sector. In 2019, Malaysia launched a 5-year national strategic plan for viral hepatitis control and has been expanding HCV testing and treatment to the primary care and community levels, while actively engaging key populations in services for hepatitis care. The Ministry of Health (MoH) is seeking to specifically understand how to better target HCV services at men who have sex with men (MSM); HCV self-testing could increase the uptake of HCV testing among this group. METHODS: We aim to integrate HCV antibody self-testing into an existing online platform used for HIV self-testing, to evaluate the acceptability and impact of an online HCV self-testing programme in Malaysia. This is a non-blinded parallel group quasi-randomised superiority study comparing HCV self-testing via an online distribution model with the standard care, which involves attending a clinic for facility-based HCV antibody testing (control, 2:1). Participants will be randomised to either the HCV self-testing via online distribution arm, in which either an oral fluid- or blood-based HCV self-test kit will be mailed to them, or the control arm, where they will be provided with information about the nearest centre with HCV testing. The primary outcome is the number and proportion of participants who report completion of testing. Secondary outcomes include the number and proportion of participants who (a) receive a positive result and are made aware of their status, (b) are referred to and complete HCV RNA confirmatory testing, and (c) start treatment. Acceptability, feasibility, attitudes around HCV testing, and cost will also be evaluated. The target sample size is 750 participants. DISCUSSION: This study is one of the first in the world to explore the real-world impact of HCV self-testing on key populations using online platforms and compare this with standard HCV testing services. The outcomes of this study will provide critical evidence about testing uptake, linkage to care, acceptability, and any social harms that may emerge due to HCV self-testing. TRIAL REGISTRATION: ClinicalTrials.gov NCT04982718.

Assessing the impact of simplified HCV care on linkage to care amongst high-risk patients at primary healthcare clinics in Malaysia: a prospective observational study.

INTRODUCTION: To achieve the elimination of hepatitis C virus (HCV), substantial scale-up in access to testing and treatment is needed. This will require innovation and simplification of the care pathway, through decentralisation of testing and treatment to primary care settings and task-shifting to non-specialists. The objective of this study was to evaluate the feasibility and effectiveness of decentralisation of HCV testing and treatment using rapid diagnostic tests (RDTs) in primary healthcare clinics (PHCs) among high-risk populations, with referral of seropositive patients for confirmatory viral load testing and treatment. METHODS: This observational study was conducted between December 2018 and October 2019 at 25 PHCs in three regions in Malaysia. Each PHC was linked to one or more hospitals, for referral of seropositive participants for confirmatory testing and pretreatment evaluation. Treatment was provided in PHCs for non-cirrhotic patients and at hospitals for cirrhotic patients. RESULTS: During the study period, a total of 15 366 adults were screened at the 25 PHCs, using RDTs for HCV antibodies. Of the 2020 (13.2%) HCV antibody-positive participants, 1481/2020 (73.3%) had a confirmatory viral load test, 1241/1481 (83.8%) were HCV RNA-positive, 991/1241 (79.9%) completed pretreatment assessment, 632/991 (63.8%) initiated treatment, 518/632 (82.0%) completed treatment, 352/518 (68.0%) were eligible for a sustained virological response (SVR) cure assessment, 209/352 (59.4%) had an SVR cure assessment, and SVR was achieved in 202/209 (96.7%) patients. A significantly higher proportion of patients referred to PHCs initiated treatment compared with those who had treatment initiated at hospitals (71.0% vs 48.8%, p<0.001). CONCLUSIONS: This study demonstrated the effectiveness and feasibility of a simplified decentralised HCV testing and treatment model in primary healthcare settings, targeting high-risk groups in Malaysia. There were good outcomes across most steps of the cascade of care when treatment was provided at PHCs compared with hospitals.

Experimental evolution of a fungal pathogen into a gut symbiont.

Gut microbes live in symbiosis with their hosts, but how mutualistic animal-microbe interactions emerge is not understood. By adaptively evolving the opportunistic fungal pathogen Candida albicans in the mouse gastrointestinal tract, we selected strains that not only had lost their main virulence program but also protected their new hosts against a variety of systemic infections. This protection was independent of adaptive immunity, arose as early as a single day postpriming, was dependent on increased innate cytokine responses, and was thus reminiscent of "trained immunity." Because both the microbe and its new host gain some advantages from their interaction, this experimental system might allow direct study of the evolutionary forces that govern the emergence of mutualism between a mammal and a fungus.

ß-glucan Exposure on the Fungal Cell Wall Tightly Correlates with Competitive Fitness of Candida Species in the Mouse Gastrointestinal Tract.

Candida albicans is responsible for ~400,000 systemic fungal infections annually, with an associated mortality rate of 46-75%. The human gastrointestinal (GI) tract represents the largest natural reservoir of Candida species and is a major source of systemic fungal infections. However, the factors that control GI colonization by Candida species are not completely understood. We hypothesized that the fungal cell wall would play an important role in determining the competitive fitness of Candida species in the mammalian GI tract. To test this hypothesis, we generated a systematic collection of isogenic C. albicans cell wall mutants and measured their fitness in the mouse GI tract via quantitative competition assays. Whereas a large variation in competitive fitness was found among mutants, no correlation was observed between GI fitness and total levels of individual cell wall components. Similar results were obtained in a set of distantly-related Candida species, suggesting that total amounts of individual cell wall components do not determine the ability of fungi to colonize the GI tract. We then subjected this collection of Candida strains and species to an extensive quantitative phenotypic profiling in search for features that might be responsible for their differences in GI fitness, but found no association with the ability to grow in GI-mimicking and stressful environments or with in vitro and in vivo virulence. The most significant association with GI fitness was found to be the strength of signaling through the Dectin-1 receptor. Using a quantitative assay to measure the amount of exposed ß-glucan on the surface of fungal cells, we found this parameter, unlike total ß-glucan levels, to be strongly predictive of competitive fitness in the mouse GI tract. These data suggest that fungal cell wall architecture, more so than its crude composition, critically determines the ability of fungi to colonize the mammalian GI tract. In particular, recognition of exposed ß-glucan by Dectin-1 receptor appears to severely limit Candida GI fitness and hence represents a promising target to reduce fungal colonization in patients at risks of systemic candidiasis.

Pathogenicity of Salmonella enterica in Caenorhabditis elegans relies on disseminated oxidative stress in the infected host.

Feeding Caenorhabditis elegans with Salmonella enterica serovar Typhimurium significantly shortens the lifespan of the nematode. S. Typhimurium-infected C. elegans, stained with 2',7'-dichlorodihydrofluorescein diacetate which fluoresces upon exposure to reactive oxygen species, revealed intestinal luminal staining that along with the time of infection progressed to a strong staining in the hypodermal tissues of the nematode. Still, we could not detect invasion beyond the nematode's intestinal epithelium at any stage of the infection. A similar dispersion of oxidative response was also noted in nematodes infected with S. Dublin, but not with non-pathogenic Escherichia coli or the defined pathogen Burkholderia thailandensis. Addition of catalase or the reductant ascorbic acid significantly restored the lifespan of S. Typhimurium-infected nematodes. Mutational inactivation of the bacterial thioredoxin 1 resulted in total ablation of the hypodermal oxidative response to infection, and in a strong attenuation of virulence. Virulence of the thioredoxin 1 mutant was restored by trans-complementation with redox-active variants of thioredoxin 1 or, surprisingly, by exposing the thioredoxin 1 mutant to sublethal concentrations of the disulphide catalyst copper chloride prior to infection. In summary, our observations define a new aspect in virulence of S. enterica that apparently does not involve the classical invasive or intracellular phenotype of the pathogen, but that depends on the ability to provoke overwhelming systemic oxidative stress in the host through the redox activity of bacterial thioredoxin 1.

Modulation of Caenorhabditis elegans infection sensitivity by the LIN-7 cell junction protein.

In Caenorhabditis elegans, the LIN-2/7/10 protein complex regulates the activity of signalling proteins. We found that inhibiting lin-7 function, and also lin-2 and lin-10, resulted in enhanced C. elegans survival after infection by Burkholderia spp., implicating a novel role for these genes in modulating infection outcomes. Genetic experiments suggested that this infection phenotype is likely caused by modulation of the DAF-2 insulin/IGF-1 signalling pathway. Supporting these observations, yeast two-hybrid assays confirmed that the LIN-2 PDZ domain can physically bind to the DAF-2 C-terminus. Loss of lin-7 activity also altered DAF-16 nuclear localization kinetics, indicating an additional contribution by hsf-1. Unexpectedly, silencing lin-7 in the hypodermis, but not the intestine, was protective against infection, implicating the hypodermis as a key tissue in this phenomenon. Finally, consistent with lin-7 acting as a general host infection factor, lin-7 mutants also exhibited enhanced survival upon infection by two other Gram-negative pathogens, Pseudomonas and Salmonella spp.

Small-molecular virulence inhibitors show divergent and immunomodulatory effects in infection models of Salmonella enterica serovar Typhimurium.

The virulence-associated Salmonella pathogenicity island 2 (SPI2) type III secretion system supports intracellular replication of Salmonella enterica serovar Typhimurium in macrophage-like RAW264.7 cells. In contrast, the salicylidene acylhydrazide INP0010 and the benzimidazole omeprazole prevent virulence factor-mediated replication of S. Typhimurium in these cells. Here we show that INP0010 enhances expression of inducible nitric oxide synthase (iNOS), nitric oxide (NO) production, the oxidative burst and tumour necrosis factor-alpha (TNFα) release in infected RAW264.7 cells. INP0010 also inhibited SPI2 activity in RAW264.7 cells. The ability of INP0010 to suppress bacterial intracellular replication correlated with NO production. The iNOS inhibitor N-monomethyl-l-arginine restored SPI2 activity and antagonised the bacteriostatic effect of INP0010. Omeprazole, which inhibited iNOS expression in RAW264.7 cells, likewise antagonised INP0010. In infected epithelioid MDCK cells that did not express NO upon infection, INP0010 enhanced bacterial intracellular replication. In Caenorhabditis elegans, INP0010 significantly attenuated the virulence of S. Typhimurium. In this infection model, the attenuating effect of INP0010 was further enhanced by omeprazole. These results demonstrate that chemically unrelated virulence inhibitors may act in an antagonistic or additive manner, that their effect depends on the infection model applied, and that the attenuating effects of INP0010 in part relate to its ability to promote the SPI2 antagonist NO.

Gene expression profiling reveals the defining features of the classical, intermediate, and nonclassical human monocyte subsets.

New official nomenclature subdivides human monocytes into 3 subsets: the classical (CD14(++)CD16(-)), intermediate (CD14(++)CD16(+)), and nonclassical (CD14(+)CD16(++)) monocytes. This introduces new challenges, as monocyte heterogeneity is mostly understood based on 2 subsets, the CD16(-) and CD16(+) monocytes. Here, we comprehensively defined the 3 circulating human monocyte subsets using microarray, flow cytometry, and cytokine production analysis. We find that intermediate monocytes expressed a large majority (87%) of genes and surface proteins at levels between classical and nonclassical monocytes. This establishes their intermediary nature at the molecular level. We unveil the close relationship between the intermediate and nonclassic monocytes, along with features that separate them. Intermediate monocytes expressed highest levels of major histocompatibility complex class II, GFRα2 and CLEC10A, whereas nonclassic monocytes were distinguished by cytoskeleton rearrangement genes, inflammatory cytokine production, and CD294 and Siglec10 surface expression. In addition, we identify new features for classic monocytes, including AP-1 transcription factor genes, CLEC4D and IL-13Rα1 surface expression. We also find circumstantial evidence supporting the developmental relationship between the 3 subsets, including gradual changes in maturation genes and surface markers. By comprehensively defining the 3 monocyte subsets during healthy conditions, we facilitate target identification and detailed analyses of aberrations that may occur to monocyte subsets during diseases.

Identification of novel functional differences in monocyte subsets using proteomic and transcriptomic methods.

Human blood monocytes can be broadly divided into two distinct subsets: CD14+CD16- and CD14+/lowCD16+ subsets. Perturbation in their proportions in the blood has been observed in several disease conditions. Although numerous phenotypic and functional differences between the two subsets have already been described, the roles contributed by each subset during homeostasis or disease conditions are still largely unclear. To uncover novel differences to aid in elucidating their functions, we perform a global analysis of the two subsets utilizing both proteomics and transcriptomics approaches. From the proteomics and transcriptomics data, the expression of 613 genes by the two subsets is detected at both the protein and mRNA levels. These 613 genes are assessed for up-regulation in each subset at the protein and mRNA levels using a cutoff fold change of > or =|1.5| between subsets. Proteins and mRNAs up-regulated in each subset are then mapped in silico into biological functions. This mapping reveals copious functional differences between the subsets, many of which are seen at both protein and mRNA levels. For instance, expression of genes involved in F(CY) receptor-mediated phagocytosis are up-regulated in the CD14+/lowCD16+ subset, while those involved in antimicrobial function are up-regulated in the CD14+CD16- subset. We uncover novel functional differences between the monocyte subsets from differences in gene expression at the protein and mRNA levels. These functional differences would provide new insights into the different roles of the two monocyte subsets in regulating innate and adaptive immune responses.