49 research outputs found
Recommended from our members
APOBEC3G expression is dysregulated in primary HIV-1 infection and polymorphic variants influence CD4+ T-cell counts and plasma viral load
OBJECTIVES: In the absence of HIV-1 virion infectivity factor (Vif), cellular cytosine deaminases such as apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) inhibit the virus by inducing hypermutations on viral DNA, among other mechanisms of action. We investigated the association of APOBEC3G mRNA levels and genetic variants on HIV-1 susceptibility, and early disease pathogenesis using viral load and CD4 T-cell counts as outcomes. METHODS: Study participants were 250 South African women at high risk for HIV-1 subtype C infection. We used real-time PCR to measure the expression of APOBEC3G in HIV-negative and HIV-positive primary infection samples. APOBEC3G variants were identified by DNA re-sequencing and TaqMan genotyping. RESULTS: We found no correlation between APOBEC3G expression levels and plasma viral loads (r = 0.053, P = 0.596) or CD4 T-cell counts (r = 0.030, P = 0.762) in 32 seroconverters. APOBEC3G expression levels were higher in HIV-negative individuals as compared with HIV-positive individuals (P < 0.0001), including matched pre and postinfection samples from the same individuals (n = 13, P < 0.0001). Twenty-four single nucleotide polymorphisms, including eight novel, were identified within APOBEC3G by re-sequencing and genotyping. The H186R mutation, a codon-changing variant in exon 4, and a 3' extragenic mutation (rs35228531) were associated with high viral loads (P = 0.0097 and P < 0.0001) and decreased CD4 T-cell levels (P = 0.0081 and P < 0.0001), respectively. CONCLUSION: These data suggest that APOBEC3G transcription is rapidly downregulated upon HIV-1 infection. During primary infection, APOBEC3G expression levels in peripheral blood mononuclear cells do not correlate with viral loads or CD4 T-cell counts. Genetic variation of APOBEC3G may significantly affect early HIV-1 pathogenesis, although the mechanism remains unclear and warrants further investigation
Conserved positive selection signals in gp41 across multiple subtypes and difference in selection signals detectable in gp41 sequences sampled during acute and chronic HIV-1 subtype C infection
<p>Abstract</p> <p>Background</p> <p>The high diversity of HIV variants driving the global AIDS epidemic has caused many to doubt whether an effective vaccine against the virus is possible. However, by identifying the selective forces that are driving the ongoing diversification of HIV and characterising their genetic consequences, it may be possible to design vaccines that pre-empt some of the virus' more common evasion tactics. One component of such vaccines might be the envelope protein, gp41. Besides being targeted by both the humoral and cellular arms of the immune system this protein mediates fusion between viral and target cell membranes and is likely to be a primary determinant of HIV transmissibility.</p> <p>Results</p> <p>Using recombination aware analysis tools we compared site specific signals of selection in gp41 sequences from different HIV-1 M subtypes and circulating recombinant forms and identified twelve sites evolving under positive selection across multiple major HIV-1 lineages. To identify evidence of selection operating during transmission our analysis included two matched datasets sampled from patients with acute or chronic subtype C infections. We identified six gp41 sites apparently evolving under different selection pressures during acute and chronic HIV-1 infections. These sites mostly fell within functional gp41 domains, with one site located within the epitope recognised by the broadly neutralizing antibody, 4E10.</p> <p>Conclusion</p> <p>Whereas these six sites are potentially determinants of fitness and are therefore good candidate targets for subtype-C specific vaccines, the twelve sites evolving under diversifying selection across multiple subtypes might make good candidate targets for broadly protective vaccines.</p
Antibiotic resistance trends of ESKAPE pathogens in Kwazulu-Natal, South Africa: A five-year retrospective analysis.
BACKGROUND: To combat antimicrobial resistance, the World Health Organization developed a global priority pathogen list of antibiotic-resistant bacteria for prioritisation of research and development of new, effective antibiotics. OBJECTIVE: This study describes a five-year resistance trend analysis of the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp., from Kwazulu-Natal, South Africa. METHODS: This retrospective study used National Health Laboratory Services data on 64 502 ESKAPE organisms isolated between 2011 and 2015. Susceptibility trends were ascertained from minimum inhibitory concentrations and interpreted using Clinical and Laboratory Standards Institute guidelines. RESULTS: S. aureus was most frequently isolated (n = 24, 495, 38%), followed by K. pneumoniae (n = 14, 282, 22%). Decreasing rates of methicillin-resistant S. aureus (28% to 18%, p 70%). CONCLUSION: This study describes the magnitude of antimicrobial resistance in KwaZulu-Natal and provides a South African perspective on antimicrobial resistance in the global priority pathogen list, signalling the need for initiation or enhancement of antimicrobial stewardship and infection control measures locally
Recommended from our members
Association of polymorphisms in the LEDGF/p75 gene (PSIP1) with susceptibility to HIV-1 infection and disease progression
OBJECTIVE: LEDGF/p75, encoded by the PSIP1 gene, interacts with HIV-1 integrase and targets HIV-1 integration into active genes. We investigated the influence of polymorphisms in PSIP1 on HIV-1 acquisition and disease progression in black South Africans. METHODS: Integrase binding domain of LEDGF/p75 was sequenced in 126 participants. Four haplotype tagging SNPs rs2277191, rs1033056, rs12339417 and rs10283923 referred to as SNP1, SNP2, SNP3 and SNP4, respectively, and one exonic SNP rs61744944 (SNP5, Q472L) were genotyped in 195 HIV-1 seronegative, 52 primary and 403 chronically infected individuals using TaqMan assays. LEDGF/p75 expression was quantified by real-time RT-PCR. The impact of Q472L mutation on the interaction with HIV_1 IN was measured by AlphaScreen. RESULTS: rs2277191 (SNP1) A was more frequent among seropositives (P = 0.06, Fisher's exact test). Among individuals followed longitudinally SNP1A trended towards association with higher likelihood of HIV-1 acquisition [relative hazard (RH) = 2.21, P = 0.08; Cox model] and it was also associated with rapid disease progression (RH = 5.98, P = 0.04; Cox model) in the recently infected (primary infection) cohort. rs12339417 (SNP3)C was associated with slower decline of CD4(+) T cells (P = 0.02) and lower messenger RNA (mRNA) levels of LEDGF/p75 (P < 0.01). Seroconverters had higher preinfection mRNA levels of LEDGF/p75 (P < 0.01) and these levels decreased after HIV-1 infection (P = 0.02). CONCLUSIONS: Genetic variants of PSIP1 may affect HIV-1 outcomes. Further studies are needed to confirm the effect of genetic variation of PSIP1 on HIV-1 pathogenesis in different cohorts
Recommended from our members
Co-enrollment in multiple HIV prevention trials — Experiences from the CAPRISA 004 Tenofovir gel trial
Background: In settings where multiple HIV prevention trials are conducted in close proximity, trial participants may attempt to enroll in more than one trial simultaneously. Co-enrollment impacts on participant's safety and validity of trial results. We describe our experience, remedial action taken, inter-organizational collaboration and lessons learnt following the identification of co-enrolled participants. Experiences: Between February and April 2008, we identified 185 of the 398 enrolled participants as ineligible. In violation of the study protocol exclusion criteria, there was simultaneous enrollment in another HIV prevention trial (ineligible co-enrolled, n = 135), and enrollment of women who had participated in a microbicide trial within the past 12 months (ineligible not co-enrolled, n = 50). Following a complete audit of all enrolled participants, ineligible participants were discontinued via study exit visits from trial follow-up. Custom-designed education program on co-enrollment impacting on participants' safety and validity of the trial results was implemented. Shared electronic database between research units was established to enable verification of each volunteer's trial participation and to prevent future co-enrollments. Lessons learnt: Interviews with ineligible enrolled women revealed that high-quality care, financial incentives, altruistic motives, preference for sex with gel, wanting to increase their likelihood of receiving active gel, perceived low risk of discovery and peer pressure are the reasons for their enrollment in the CAPRISA 004 trial. Conclusion: Instituting education programs based on the reasons reported by women for seeking enrollment in more than one trial and using a shared central database system to identify co-enrollments have effectively prevented further co-enrollments
Recommended from our members
Beyond syndromic management: Opportunities for diagnosis-based treatment of sexually transmitted infections in low- and middle-income countries
Introduction
In light of the limited impact the syndromic management approach has had on the global sexually transmitted infection (STI) epidemic, we assessed a care model comprising point-of-care (POC) STI testing, immediate treatment, and expedited partner therapy (EPT) among a cohort of young women at high HIV risk in South Africa.
Methods and findings
HIV negative women presenting for STI care underwent POC testing for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV), and swabs were sent for NG culture and susceptibility testing. Results were available within 2 hours and women with STIs were immediately treated and offered EPT packs, including medication, condoms, and information for sexual partners. An EPT questionnaire was administered after one week, and women retested for STIs after 6 and 12 weeks. 267 women, median age 23 (IQR 21–26), were recruited and 88.4% (236/267) reported genital symptoms. STI prevalence was CT 18.4% (95%CI 13.7–23.0), NG 5.2% (95%CI 2.6–7.9) and TV 3.0% (95%CI 1.0–5.0). After 12 weeks, all but one NG and two CT infections were cleared. No cephalosporin-resistant NG was detected. Of 63/267 women (23.6%) diagnosed with STIs, 98.4% (62/63) were offered and 87.1% (54/62) accepted EPT. At one week 88.9% (48/54) stated that their partner had taken the medication. No allergic reactions or social harms were reported. Of 51 women completing 6-week follow up, detection rates were lower amongst women receiving EPT (2.2%, 1/46) compared to those who did not (40.0%, 2/5), p = 0.023. During focus group discussions women supported the care model, because they received a rapid, specific diagnosis, and could facilitate their partners’ treatment.
Conclusions
POC STI testing and EPT were acceptable to young South African women and their partners, and could play an important role in reducing STI reinfection rates and HIV risk. Larger studies should evaluate the feasibility and cost-effectiveness of implementing this strategy at population level
Plasma cytokine levels during acute HIV-1 infection predict HIV disease progression
BACKGROUND: Both T-cell activation during early HIV-1 infection and soluble markers of immune activation during chronic infection are predictive of HIV disease progression. Although the acute phase of HIV infection is associated with increased pro-inflammatory cytokine production, the relationship between cytokine concentrations and HIV pathogenesis is unknown. OBJECTIVES: To identify cytokine biomarkers measurable in plasma during acute HIV-1 infection that predict HIV disease progression. DESIGN: Study including 40 South African women who became infected with HIV-1 and were followed longitudinally from the time of infection. METHODS: The concentrations of 30 cytokines in plasma from women with acute HIV-1 infection were measured and associations between cytokine levels and both viral load set point 12 months postinfection and time taken for CD4 cell counts to fall below 350 cells/microl were determined using multivariate and Cox proportional hazards regression. RESULTS: We found that the concentrations of five plasma cytokines, IL-12p40, IL-12p70, IFN-gamma, IL-7 and IL-15 in women with acute infection predicted 66% of the variation in viral load set point 12 months postinfection. IL-12p40, IL-12p70 and IFN-gamma were significantly associated with lower viral load, whereas IL-7 and IL-15 were associated with higher viral load. Plasma concentrations of IL-12p40 and granulocyte-macrophage colony-stimulating factor during acute infection were associated with maintenance of CD4 cell counts above 350 cells/microl, whereas IL-1alpha, eotaxin and IL-7 were associated with more rapid CD4 loss. CONCLUSION: A small panel of plasma cytokines during acute HIV-1 infection was predictive of long-term HIV disease prognosis in this group of South African women
The role of emergent champions in policy implementation for decentralised drug-resistant tuberculosis care in South Africa.
OBJECTIVE: Champions are recognised as important to driving organisational change in healthcare quality improvement initiatives in high-income settings. In low-income and middle-income countries with a high disease burden and constrained human resources, their role is highly relevant yet understudied. Within a broader study on policy implementation for decentralised drug-resistant tuberculosis care in South Africa, we characterised the role, strategies and organisational context of emergent policy champions. DESIGN: Interviews with 34 healthcare workers in three South African provinces identified the presence of individuals who had a strong influence on driving policy implementation forward. Additional interviews were conducted with 13 participants who were either identified as champions in phase II or were healthcare workers in facilities in which the champions operated. Thematic analyses using a socio-ecological framework further explored their strategies and the factors enabling or obstructing their agency. RESULTS: All champions occupied senior managerial posts and were accorded legitimacy and authority by their communities. 'Disease-centred' champions had a high level of clinical expertise and placed emphasis on clinical governance and clinical outcomes, while 'patient-centred' champions promoted pathways of care that would optimise patients' recovery while minimising disruption in other spheres of their lives. Both types of champions displayed high levels of resourcefulness and flexibility to adapt strategies to the resource-constrained organisational context. CONCLUSION: Policymakers can learn from champions' experiences regarding barriers and enablers to implementation to adapt policy. Research is needed to understand what factors can promote the sustainability of champion-led policy implementation, and to explore best management practices to support their initiatives
Recruitment of high risk women for HIV prevention trials: baseline HIV prevalence and sexual behavior in the CAPRISA 004 tenofovir gel trial
<p>Abstract</p> <p>Background</p> <p>Young women in sub-Saharan Africa bear a disproportionate burden of HIV infection compared to men but have limited options to reduce their HIV risk. Microbicides could fill an important HIV prevention gap for sexually active women who are unable to successfully negotiate mutual monogamy or condom use.</p> <p>Purpose</p> <p>This paper describes the baseline sample characteristics in the CAPRISA 004 trial which assessed the safety and effectiveness of the vaginal microbicide, 1% tenofovir gel for HIV prevention in South Africa.</p> <p>Methods</p> <p>This analysis assessed the baseline demographic, clinical and sexual behavior data of women screened and enrolled into the trial. The characteristics were summarized using descriptive summary measures; expressed as means and percent for categorical variables.</p> <p>Results</p> <p>HIV prevalence at screening was 25.8% [95% Confidence Interval (CI):23.9-27.7). Of the 889 eligibly enrolled women who contributed follow-up data, rural participants recruited from a family planning (FP) clinic were younger, more likely to be living apart from their regular partner, reported lower coital frequency, had lower condom use (p < 0.001). In contrast, urban participants recruited from a sexually transmitted disease (STD) clinic reported higher numbers of lifetime sexual partners, new partners in the last 30 days and receiving money in exchange for sex (p < 0.001).</p> <p>Conclusion</p> <p>The populations selected provide suitable diverse target groups for HIV prevention intervention studies.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00441298">NCT 00441298</a></p
"We had to manage what we had on hand, in whatever way we could": Adaptive responses in policy for decentralised drug-resistant tuberculosis care in South Africa
Karina Kielmann - ORCID: 0000-0001-5519-1658
https://orcid.org/0000-0001-5519-1658Replaced AM with VoR 2021-02-19.In 2011, the South African National TB Programme launched a policy of decentralized management of drug-resistant tuberculosis (DR-TB) in order to expand the capacity of facilities to treat patients with DR-TB, minimize delays to access care and improve patient outcomes. This policy directive was implemented to varying degrees within a rapidly evolving diagnostic and treatment landscape for DR-TB, placing new demands on already-stressed health systems. The variable readiness of district-level systems to implement the policy prompted questions not only about differences in health systems resources but also front-line actors’ capacity to implement change in resource-constrained facilities. Using a grounded theory approach, we analysed data from indepth interviews and small group discussions conducted between 2016 and 2018 with managers (n = 9), co-ordinators (n = 15), doctors (n = 7) and nurses (n = 18) providing DR-TB care. Data were collected over two phases in district-level decentralized sites of three South African provinces. While health systems readiness assessments conventionally map the availability of ‘hardware’, i.e. resources and skills to deliver an intervention, a notable absence of systems ‘hardware’ meant that systems ‘software’, i.e. health care workers (HCWs) agency, behaviours and interactions provided the basis of locally relevant strategies for decentralized DR-TB care. ‘Software readiness’ was manifest in four areas of DR-TB care: re-organization of service delivery, redressal of resource shortages, creation of treatment adherence support systems and extension of care parameters for vulnerable patients. These strategies demonstrate adaptive capacity and everyday resilience among HCW to withstand the demands of policy change and innovation in stressed systems. Our work suggests that a useful extension of health systems ‘readiness’ assessments would include definition and evaluation of HCW ‘software’ and adaptive capacities in the face of systems hardware gaps.The work presented in this paper was supported by the Joint Health Systems Research Initiative, jointly supported by the Department for International Development (DFID), the Economic and Social Research Council (ESRC), the Medical Research Council (MRC) and the Wellcome Trust (Grant# MR/N015924/1). This UK funded award is part of the EDCTP2 programme supported by the European Union. Ethical approval for the project was obtained through the University of Cape Town Human Research Ethics Committee (HREC REF 350/2016). HC is supported by a Wellcome Trust Fellowship. The authors wish to thank and acknowledge Dr. Norbert Ndjeka (SA NDOH), the provinces of the W Cape, E Cape, KZN for all their input and assistance.https://doi.org/10.1093/heapol/czaa14736pubpub