215 research outputs found

    The impact of sexually transmitted infections (STI) and genital tract inflammation on HIV-1 acquisition and rate of disease progression in subtype C infected women.

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    Ph. D. University of KwaZulu-Natal, Durban 2014.Introduction: Women carry more than half the burden of HIV disease globally and this burden is even higher in sub-Saharan Africa (SSA). Young women, in particular, are at disproportionate risk of HIV infection in South Africa. Understanding risk behaviours and factors associated with ability to negotiate safe sex and condom use is one of the key elements in curbing the spread of HIV. Sexually transmitted infections (STI) and bacterial vaginosis (BV), which cause female genital tract inflammation, have been identified as key drivers of the HIV epidemic. This inflammation, which is also present in the absence of symptoms, is associated with increased susceptibility to HIV infection. Although syndromic management of symptomatic STIs or BV at the first encounter with a health care provider is an important public health measure, its effectiveness is minimised because a substantial proportion of individuals have either asymptomatic infections or fail to recognise signs and symptoms of STI and are therefore excluded. Most new HIV infections in SSA occur among young people and particularly among young girls. Prompt diagnosis of acute HIV infection (AHI) is critical and benefits the individual as well as providing opportunities for public health intervention. In South Africa, the majority of HIV infections are due to infection with HIV-1 subtype C for which there is limited data compared to subtype-B HIV-1 infections. The overall aim of this study was to assess the impact of BV, STIs, and associated genital tract inflammation on acquisition of HIV-1 subtype C infections; and evaluate the rate of subsequent disease progression in women. The objectives were: i. to investigate STIs and genital tract inflammation as risk factors for HIV infection in high risk women and adequacy of syndromic management; ii. to evaluate the challenges associated with diagnosing recently acquired (acute) HIV infection in a subtype C prevalent population; iii. and to evaluate the relationship between clinical disease progression and genital and or systemic inflammation in high-risk women who became infected with HIV. We assessed the adequacy of syndromic diagnosis of STIs, compared with laboratory diagnosis of STIs, and evaluated the association between STI diagnosis and the risk of HIV acquisition in a cohort of high-risk women. Genital cytokine profiles and the degree of inflammation associated with common STIs and bacterial vaginosis were assessed. The most common signs and symptoms of acute HIV infection (AHI) were described and a clinical algorithm to identify acute HIV cases was developed. We investigated rates of HIV disease progression of subtype C–infected South African women. Methods: The CAPRISA 002 study was a prospective cohort study established to examine the pathogenesis and natural history of HIV-1 subtype C infection and to describe the immunologic, virologic and clinical characteristics of acute and early infection in KwaZulu Natal, South Africa. A total of 775 high-risk women were screened for HIV infection, and 245 HIV-uninfected women were enrolled into the study. At each monthly visit for a total of 24 months behavioural and clinical data were collected. Cervico-vaginal lavage (CVL) samples were collected at enrolment and at each six month follow-up visits and were tested for STI pathogens (including Chlamydia trachomatis, Neisseria gonorrhoeae, herpes simplex virus type 2 (HSV-2) and Trichomonas vaginalis) and bacterial vaginosis. Forty-two cytokines were measured from the CVL and 13 from the plasma samples at enrolment. All women received monthly HIV-1 antibody and RNA testing and were assessed for AHI. Signs and symptoms at the visit with HIV-1 antibody or HIV-1 RNA positive test were compared to HIV negative visits. Logistic regression identified clinical predictors of AHI and a model-based score was assigned to each predictor to create a risk score for every woman. All women who seroconverted were followed up for more than five years and monitored for HIV disease progression. Rapid disease progression was defined as CD4+ T cell count decline to <350 cells/μl within two years post-infection. Serial clinical and laboratory assessments were compared using survival analysis and logistic regression models. CAPRISA had established several cohorts of HIV negative women to determine the feasibility of establishing cohorts and sites for HIV biomedical prevention trials. Women seroconverting in these studies were referred to the CAPRISA 002 study for longitudinal follow-up for HIV post seroconversion. Results: In this study, the HIV-1 prevalence at screening was 59.6% (95% CI: 55.9% to 62.8%). During a total of 390 person-years of follow-up, 28 new infections occurred, yielding a seroincidence rate of 7.2 (95% CI: 4.5 to 9.8) per 100 person-years. A total of 62 participants, including seroconvertors from other CAPRISA cohorts, were enrolled into the acute HIV infection Women from the HIV-1 negative cohort generally demonstrated a high level of knowledge on HIV/AIDS, and 60.3% reported use of condoms. Reported condom use at last sexual encounter varied slightly by partner type (57.0% with steady versus 64.4% with casual partners; p = 0.36), whilst self-perceived ability to choose to use a condom was significantly lower with steady partners compared to casual partners (20.8% versus 53.9%; p=0.01). An important finding was that vaginal discharge was a poor predictor of laboratory-diagnosed STIs, as only 12.3% of women (25/204) who had a laboratory-confirmed discharge causing pathogen had clinical evidence of a discharge (yielding a sensitivity of 12.3% and a specificity of 93.8%). CVL cytokine concentrations did not differ between women with asymptomatic or symptomatic STIs; and were elevated in women with either asymptomatic or symptomatic STIs compared to women with no STIs or BV. Women with chlamydia or gonorrhoea had the highest genital cytokine concentrations, with 17/42 and 14/42 of the cytokines measured in CVL being up-regulated compared with women with no infections, respectively. While BV was associated with elevated pro-inflammatory cytokine concentrations in CVL, women with BV had lower levels of chemokines and haematopoietic cytokines than women with no infections or BV. HSV-2 reactivation was inflammatory, but yielded a comparatively lower level of inflammation than Chlamydia or gonnorhoea. Trichomoniasis, despite being relatively common in this cohort, did not cause significant changes in genital tract cytokine concentrations compared to women with no infections or BV. Genital infections did not influence plasma cytokine concentrations, suggesting that the compartments were not linked with respect to cytokine responses. Although laboratorydiagnosed STIs were associated with increased risk of HIV infection [hazard ratio, 3.3 (95% confidence interval, 1.5 – 7.2)], clinical symptoms were not. Of the women who became infected, factors predictive of AHI included age, 25 years (OR = 3.2; 1.4 – 7.1), rash (OR = 6.1; 2.4 –15.4), sore throat (OR = 2.7; 1.0 – 7.6), weight loss (OR = 4.4; 1.5 – 13.4), genital ulcers (OR = 8.0; 1.6 – 39.5) and vaginal discharge (OR = 5.4; 1.6 – 18.4). A risk score of 2 correctly predicted AHI in 50.0% of cases. The number of signs and symptoms correlated with higher HIV-1 RNA at diagnosis (r = 0.63; p = 0.001). The 62 acutely infected women were identified at a median of 42 days post-infection (IQR = 34 – 59). Mean CD4 count dropped by 39.6% at 3 months and 46.7% at 6 months post-infection in women with pre-infection measurements. CD4 decline to <350 cells/μL occurred in 31%, 44%, and 55% of women at 1, 2, and 3 years post-infection, respectively, and to <500 cells/μL in 69%, 79%, and 81% at equivalent time-points. Predictors of rapid progression were CD4 count at 3 months post-infection (hazard ratio [HR], 2.07; 95% confidence interval [CI], 1.31–3.28; P = .002), setpoint viral load (HR, 3.82; 95% CI, 1.51–9.67; P = .005), and hepatitis B coinfection (HR, 4.54; 95% CI, 1.31–15.69; P = .017). Conversely, presence of any of HLAB*1302, B*27, B*57, B*5801, or B*8101 alleles predicted non–rapid progression (HR, 0.19; 95% CI, .05–.74; P = .016). Discussion/Conclusion: This study showed that syndromic STI diagnosis, which is dependent on clinical signs of vaginal discharge, was poorly predictive of laboratory-diagnosed STIs or BV and missed a significant proportion of women with asymptomatic infections. However, the level of genital inflammation, as measured by cytokine concentrations in CVL, was similar in women with symptomatic and asymptomatic infections and therefore place women at increased risk for HIV infection. While laboratory-diagnosed STIs and the presence of inflammatory cytokines in the genital tract were associated with increased susceptibility to HIV acquisition, vaginal discharge was not. Chlamydial infection was associated with the highest genital cytokine concentrations, followed by gonorrhoea, HSV-2, trichomoniasis, and BV. In regions where HIV is prevalent and STIs are managed syndromically, targeted screening of populations at risk for STIs is critical and urgently needed. Recognition of signs and symptoms of AHI is important for early diagnosis of HIV infection. The proposed algorithm of risk-stratifying individuals for AHI provides a useful clinical tool especially in resource-limited settings where there are limited or no routinely available tests for AHI. However, validation of the algorithm on another cohort is needed to assess its utility further. Point-of-care HIV antigen or viral load testing is needed, to detect asymptomatic, antibody negative cases enabling early interventions and prevention of transmission. This cohort showed high rates of rapid disease progression, with nearly half of these subtype C–infected women progressing to a CD4+ T cell count of below 350 cells/μL within 2 years of infection. Implementing 2013 World Health Organization treatment guidelines (CD4+ T cell counts less than 500cells/μL) would require most individuals to start antiretroviral therapy within 1 year of HIV infection. The economic and health systems planning implicated by these findings need to be explored and addressed to guide policy makers as countries adopt the current WHO guidelines

    High Prevalence of inhA Promoter Mutations among Patients with Drug-Resistant Tuberculosis in KwaZulu-Natal, South Africa

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    Background Drug-resistant tuberculosis (TB) remains extremely difficult to treat because there are often few remaining active medications and limited diagnostic options to detect resistance. Resistance to isoniazid is typically caused by mutations in either katG or the inhA promoter. inhA mutations confer low-level resistance to isoniazid and cross-resistance to ethionamide while katG mutations confer high-level isoniazid resistance and no cross-resistance. Line Probe Assays (LPAs) that detect mutations in katG and inhA are currently performed on all positive TB cultures in KwaZulu-Natal province, South Africa, but the frequency of inhA mutations in drug-resistant TB patients has not been examined. Methods We sought to determine the proportion of patients who could potentially benefit from high-dose isoniazid and who may be resistant to ethionamide. We reviewed 994 LPA (Hain MTBDRplus) results at the TB reference laboratory in KwaZulu-Natal to determine the frequency of mutations in either katG or the inhA promoter. We stratified these results by drug-resistance category (i.e., MDR-TB, pre-XDR-TB, and XDR-TB) as determined by phenotypic drug-susceptibility testing. Results Among MDR- and XDR-TB isolates, the prevalence of inhA mutations without a concurrent katG mutation was 14.8% and 10.3% respectively. The prevalence of inhA mutations with OR without a katG mutation was 30.3% and 82.8%, respectively. Conclusion More than 10% of patients with MDR- and XDR-TB may benefit from high-dose isoniazid. Although ethionamide is empirically included in all MDR- and XDR-TB regimens, nearly a third of MDR-TB patients and a majority of XDR-TB patients likely have resistance to ethionamide. Laboratories performing line probe assays should report specific band patterns so that clinicians may adjust treatment regimens accordingly

    Relationship between levels of inflammatory cytokines in the genital tract and CD4+ cell counts in women with acute HIV-1 infection.

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    Inflammatory responses at mucosal surfaces after human immunodeficiency virus type 1 (HIV-1) transmission may influence disease outcome. We evaluated levels of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, IL-8, IL-10, and IL-12 in genital tract and plasma specimens from 44 women with acute HIV infection and 29 HIV-negative control women (13 of whom were women in the acute HIV infection cohort who had preinfection samples available for analysis). Women with acute HIV infection had significantly elevated levels of IL-6, IL-10, and IL-12 in genital tract specimens and elevated levels of IL-1beta, IL-8, and IL-10 in plasma specimens, compared with HIV-negative control women. Levels of IL-1beta, IL-6, and IL-8 in cervicovaginal specimens from women with acute HIV infection showed a significant inverse correlation with systemic CD4(+) cell counts, suggesting that mucosal inflammation is associated with low CD4(+) cell counts during acute HIV infection

    Antibiotic resistance trends of ESKAPE pathogens in Kwazulu-Natal, South Africa: A five-year retrospective analysis.

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    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

    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

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    <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

    Rifampicin mono-resistance in mycobacterium tuberculosis in KwaZulu-Natal, South Africa : A significant phenomenon in a high prevalence TB-HIV region.

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    This laboratory based study was conducted at NHLS TB Laboratory, Durban, which is the reference laboratory for culture and susceptibility testing in KwaZulu-Natal. We retrospectively determined, for the period 2007 to 2009, the proportion of RMR amongst Mycobacterium tuberculosis (MTB) isolates, that were tested for both RIF and INH, using the gold standard of culture based phenotypic drug susceptibility testing (DST). Gender and age were also analysed to identify possible risk factors for RMR.Setting: The dual epidemics of HIV-TB including MDR-TB are major contributors to high morbidity and mortality rates in South Africa. Rifampicin (RIF) resistance is regarded as a proxy for MDR-TB. Currently available molecular assays have the advantage of rapidly detecting resistant strains of MTB, but the GeneXpert does not detect isoniazid (INH) resistance and the GenoTypeMTBDRplus(LPA) assay may underestimate resistance to INH. Increasing proportions of rifampicin monoresistance resistance (RMR) have recently been reported from South Africa and other countries. Objective: This laboratory based study was conducted at NHLS TB Laboratory, Durban, which is the reference laboratory for culture and susceptibility testing in KwaZulu-Natal. We retrospectively determined, for the period 2007 to 2009, the proportion of RMR amongst Mycobacterium tuberculosis (MTB) isolates, that were tested for both RIF and INH, using the gold standard of culture based phenotypic drug susceptibility testing (DST). Gender and age were also analysed to identify possible risk factors for RMR. Design: MTB culture positive sputum samples from 16,748 patients were analysed for susceptibility to RIF and INH during the period 2007 to 2009. RMR was defined as MTB resistant to RIF and susceptible to INH. For the purposes of this study, only the first specimen from each patient was included in the analysis. Results: RMR was observed throughout the study period. The proportion of RMR varied from a low of 7.3% to a high of 10.0% [overall 8.8%]. Overall, males had a 42% increased odds of being RMR as compared to females. In comparison to the 50 plus age group, RMR was 37% more likely to occur in the 25–29 year age category. Conclusion: We report higher proportions of RMR ranging from 7.3% to 10% [overall 8.8%] than previously reported in the literature. To avoid misclassification of RMR, detected by the GeneXpert, as MDR-TB, culture based phenotypic DST must be performed on a second specimen, as recommended by the SA NDOH TB guidelines as well as WHO. We suggest that two sputum samples should be obtained at the first visit. The second sputum sample should be stored at 4uC. The latter sample is then readily available for performing additional DST (phenotypic or genotypic) for 2nd lines drugs, resulting in a decreased waiting period for DST results to become available

    Pregnancy incidence and correlates during the HVTN 503 Phambili HIV vaccine trial conducted among South African women

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    BACKGROUND: HIV prevention trials are increasingly being conducted in sub-Saharan Africa. Women at risk for HIV are also at risk of pregnancy. To maximize safety, women agree to avoid pregnancy during trials, yet pregnancies occur. Using data from the HVTN 503/"Phambili" vaccine trial, we report pregnancy incidence during and after the vaccination period and identify factors, measured at screening, associated with incident pregnancy. METHODS: To enrol in the trial, women agreed and were supported to avoid pregnancy until 1 month after their third and final vaccination ("vaccination period"), corresponding to the first 7 months of follow-up. Unsterilized women, pooled across study arms, were analyzed. Poisson regression compared pregnancy rates during and after the vaccination period. Cox proportional hazards regression identified associations with first pregnancy. RESULTS: Among 352 women (median age 23 yrs; median follow-up 1.5 yrs), pregnancy incidence was 9.6/100 women-years overall and 6.8/100 w-yrs and 11.3/100 w-yrs during and after the vaccination period, respectively [Rate Ratio = 0.60 (0.32-1.14), p = 0.10]. In multivariable analysis, pregnancy was reduced among women who: enrolled at sites providing contraception on-site [HR = 0.43, 95% CI (0.22-0.86)]; entered the trial as injectable contraceptive users [HR = 0.37 (0.21-0.67)] or as consistent condom users (trend) [HR = 0.54 (0.28-1.04)]. Compared with women with a single partner of HIV-unknown status, pregnancy rates were increased among women with: a single partner whose status was HIV-negative [HR = 2.34(1.16-4.73)] and; 2 partners both of HIV-unknown status [HR = 4.42(1.59-12.29)]. Women with 2 more of these risk factors: marijuana use, heavy drinking, or use of either during sex, had increased pregnancy incidence [HR = 2.66 (1.24-5.72)]. CONCLUSIONS: It is possible to screen South African women for pregnancy risk at trial entry. Providing injectable contraception for free on-site and supporting consistent condom use may reduce incident pregnancy. Screening should determine the substance use, partnering, and HIV status of both members of the couple for both pregnancy and HIV prevention. Trial Registration SA National Health Research Database DOH-27-0207-1539; Clinicaltrials.gov NCT0041372

    Predictors of HVTN 503 MRK-AD5 HIV-1 gag/pol/nef vaccine Induced immune responses

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    BACKGROUND: Phambili, the Merck (MRK)-Adenovirus Type 5 (Ad5) HIV-1 gag/pol/nef subtype B vaccine study, conducted in South Africa, suspended enrollment and vaccination when companion study, Step, was found non-efficacious. Although the vaccine did not prevent HIV-1 infection or lower viral-load setpoint, immune responses recognized clades B and C HIV-1 subtypes. We investigated predictors of the vaccine-induced antigen-specific immune responses. METHODS: Vaccine-induced immunogenicity was ascertained by interferon-γ ELISpot assays on the first 186 enrolled participants receiving two vaccinations. Analyses, stratified by study arm/sex, were performed on baseline demographics [sex, age, Body Mass Index (BMI), site, Adenovirus Type-5 (Ad5) titer, Herpes Simplex Virus Type-2 (HSV2) status, heavy drinking]. Multivariate logistic regression determined predictors. RESULTS: Of the 186 participants, 53.7% (n = 100) were female, median BMI was 22.5 [IQR: 20.4-27.0], 85.5% (n = 159) were Ad5 seropositive, and 18.8% (n = 35) drank heavily. All vaccine recipients responded to both clade B (n = 87; 47%) and/or C (n = 74; 40%), p = 0.17. In multivariate analysis, female sex [Adjusted Odds Ratio (AOR): 6.478; p = 0.0159], overweight/obese BMI (AOR: 0.186; p = 0.0452), and heavy drinking (AOR: 0.270; p = 0.048) significantly predicted immune response to clade C for any antigens. A marginally significant predictor of clade C-pol antigen was female sex (AOR: 3.182; p = 0.0500). CONCLUSIONS: Sex, BMI, and heavy drinking affected vaccine-induced HIV-1 specific immune responses to clade C antigens. The role of female sex and overweight/obese BMI boosting and suppressing vaccine-induced HIV-1 specific immune responses, respectively, requires elucidation, including any effect on HIV vaccine efficacy, especially in the era of colliding epidemics (HIV and obesity)

    Association of polymorphisms in the LEDGF/p75 gene (PSIP1) with susceptibility to HIV-1 infection and disease progression

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    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
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