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2.
Front Reprod Health ; 5: 1121478, 2023.
Article in English | MEDLINE | ID: mdl-36864847

ABSTRACT

HIV self-testing (HIVST) complements traditional HIV testing programmes by removing barriers and increasing access to testing for key populations, and digital interventions have been developed for HIVST to improve the testing and linkage to care experience for users. The first HIVST kit was proposed in 1986, but it took 10 years for the home sample collection (HSC) HIVST to become available and another 16 years for rapid diagnostic test HIVST to be approved by the Federal Drug Administration. Since then, studies have shown high usability and performance of HIVST, which led the World Health Organization formally recommending HIVST in 2016, and currently almost 100 countries have incorporated HIVST into their national testing strategy. Despite the popularity, HIVST present challenges around pre-and post-test counselling, as well as the ability to report results and link users to care, and digital interventions for HIVST have been introduced to address these challenges. The first digital intervention for HIVST was introduced in 2014 and showed that digital interventions could be used to distribute HIVST kits, report results and link users to care. Since then, dozens of studies have been conducted, which have validated and expanded on these early findings, but many were pilot studies with small sample sizes and lacked the standardization of indicators required to aggregate data across platforms to prove impact at scale. For digital interventions for HIVST to be championed for scale-up, they must continue to show measurable impact at larger scales, while still maintaining and standardizing data security and integrity.

3.
Int J Mol Sci ; 23(22)2022 Nov 18.
Article in English | MEDLINE | ID: mdl-36430827

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak posed a challenge for diagnostic laboratories worldwide, with low-middle income countries (LMICs) being the most affected. The polymerase chain reaction (PCR) is the gold standard method for detecting SARS-CoV-2 infection. However, the challenge with this method is that it is expensive, which has resulted in under-testing for SARS-CoV-2 infection in many LMICs. Hence, this study aimed to compare and evaluate alternative methods for the mass testing of SARS-CoV-2 infection in laboratories with limited resources to identify cost-effective, faster, and accurate alternatives to the internationally approved kits. A total of 50 residual nasopharyngeal swab samples were used for evaluation and comparison between internationally approved kits (Thermo Fisher PureLink™ RNA Isolation Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit) and alternative methods (three RNA extraction and four commercial SARS-CoV-2 RT-PCR assay kits) in terms of the cost analysis, diagnostic accuracy, and turnaround time. In terms of performance, all of the alternative RNA extraction methods evaluated were comparable to the internationally approved kits but were more cost-effective (Lucigen QuickExtract™ RNA Extraction Kit, Bosphore EX-Tract Dry Swab RNA Solution and Sonicator method) and four commercial SARS-CoV-2 RT-PCR assay kits (Nucleic Acid COVID-19 Test Kit (SARS-CoV-2), abTESTM COVID-19 qPCR I Kit, PCL COVID19 Speedy RT-PCR Kit, and PCLMD nCoV One-Step RT-PCR Kit) with a sensitivity range of 76-100% and specificity of 96-100%. The cost per sample was reduced by more than 50% when compared to internationally approved kits. When compared to the Thermo Fisher PureLink™ Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit, the alternative methods had a faster turnaround time, indicating that laboratories with limited resources may be able to process more samples in a day. The above-mentioned cost-effective, fast, and accurate evaluated alternative methods can be used in routine diagnostic laboratories with limited resources for mass testing for SARS-CoV-2 because these were comparable to the internationally approved kits, Thermo Fisher PureLink™ Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit. The implementation of alternative methods will be the most cost-effective option for testing SARS-CoV-2 infection in LMICs.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19 Testing , Laboratories , Real-Time Polymerase Chain Reaction
4.
Am J Mens Health ; 16(3): 15579883221106331, 2022.
Article in English | MEDLINE | ID: mdl-35748400

ABSTRACT

Gender-based violence (GBV) toward women is widespread and has been associated with increased HIV risk. We investigated attitudes toward GBV among men living in Rustenburg, South Africa, who were enrolled in a longitudinal HIV incidence study. Participants were 18 to 49 years old, reported high risk sexual activity in the last 3 months, and were HIV-uninfected. Attitudes toward GBV were evaluated using responses to a five-item standardized questionnaire about men perpetrating physical violence on a female spouse; responses to each item were scaled from 1 (no agreement) to 4 (strong agreement) and summed. Total scores >10 were considered permissive toward GBV. Among the 535 men analyzed, nearly half (N = 229, 42.8%) had a GBV score >10. Being young (18-24 years) (adjusted odds ratio [aOR] = 1.53, 95% confidence interval [CI] [1.06, 2.22]), having less years of education (aOR = 1.61, 95% CI [1.11, 2.32]), and reporting no current sexual partner at baseline (aOR = 2.10, 95% CI [1.06, 4.14]) were independently associated with permissive attitudes toward GBV. The following behaviors reported in the last 3 months were also associated with high GBV scores: having a new female partner (aOR = 1.78, 95% CI [1.02, 3.10]), and having had an STI (aOR = 1.85, 95% CI [1.15, 2.99]). Consuming alcohol prior to sex in the last month (aOR = 1.59, 95% CI [1.09, 2.31]) was also associated with high GBV scores. A large proportion of South African HIV-uninfected men in this analysis reported permissive attitudes toward GBV. These attitudes were associated with HIV risk behavior. Integrating GBV and HIV prevention programs is essential.


Subject(s)
Gender-Based Violence , HIV Infections , Sexually Transmitted Diseases , Adolescent , Adult , Attitude , Female , HIV Infections/epidemiology , HIV Infections/prevention & control , Humans , Male , Middle Aged , Prevalence , Sexual Behavior , South Africa/epidemiology , Young Adult
5.
PLoS One ; 17(2): e0252097, 2022.
Article in English | MEDLINE | ID: mdl-35120127

ABSTRACT

BACKGROUND: Current tuberculosis treatments leave most patients with bronchiectasis and fibrosis, permanent conditions that impair lung function and increase all-cause post-TB mortality. Host-directed therapies (HDTs) may reduce lung inflammation and hasten eradication of infection. Biomarkers can accelerate tuberculosis regimen development, but no studies have yet examined early biomarkers of TB-HDTs. METHODS: Biomarkers of inflammation and microbicidal activity were evaluated as a part of a recent phase-2 randomized controlled trial of four HDTs in 200 patients with pulmonary tuberculosis and baseline predictors of poor outcome, including CC-11050 (PDE4i), everolimus (mTORi), auranofin (oral gold salt), and ergocalciferol (vitamin D). Two of the 4 arms (CC-11050 and everolimus) showed superior recovery of lung function at day 180 compared to control; none showed accelerated eradication of MTB infection. Patients underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) on entry and day 56. PET signals were analyzed according to total, maximal, and peak glycolytic activity; CT was analyzed according to total modified Hounsfield units to assess radiodensity. Mycobactericidal activity in ex vivo whole blood culture was measured on days 42, 84, and 140. C-reactive protein (CRP) was measured at multiple time points. RESULTS: All PET/CT parameters showed highly significant reductions from baseline to day 56; however, only maximal or peak glycolytic activity showed further experimental reduction compared to controls, and only in everolimus recipients. CRP dropped precipitously during early treatment, but did so equally in all arms; over the entire period of treatment, the rate of decline of CRP tended to be greater in CC-11050 recipients than in controls but this fell short of statistical significance. Whole blood mycobactericidal activity in ex-vivo culture was enhanced by auranofin compared to controls, but not by other HDTs. CONCLUSIONS: None of these early biomarkers correctly predicted HDT effects on inflammation or infection across all four experimental arms. Instead, they each appear to show highly specific responses related to HDT mechanisms of action.


Subject(s)
Positron Emission Tomography Computed Tomography
6.
Lancet Respir Med ; 9(8): 897-908, 2021 08.
Article in English | MEDLINE | ID: mdl-33740465

ABSTRACT

BACKGROUND: Current tuberculosis treatments leave patients with clinically significant lung injury and increased all-cause mortality post-cure. Adjunctive host-directed therapies could protect the lungs, improve long-term survival, and shorten treatment duration; however, few have been tested clinically. Therefore, we aimed to assess the safety and preliminary efficacy of four host-directed therapies for tuberculosis. METHODS: In this prospective, open-label, phase 2, randomised controlled trial, patients with pulmonary tuberculosis were recruited at three clinical sites in South Africa. Eligible patients were aged 18-65 years, HIV-1-negative, and had rifampicin-susceptible Mycobacterium tuberculosis, a sputum Xpert cycle threshold of less than 20, and moderately advanced or far advanced disease on chest radiography. By use of numbers generated in blocks of ten and stratification by site, eligible patients were randomly assigned (1:1:1:1:1) to receive one of the four oral host-directed treatments plus standard tuberculosis treatment or standard treatment alone (the control group). Host-directed treatments were: CC-11050 (200 mg twice daily, taken with food; day 1-112); everolimus (0·5 mg/day; day 1-112); auranofin (3 mg/day for seven doses, then 6 mg/day; day 1-112); and ergocalciferol (5 mg on day 1, then 2·5 mg on day 28 and day 56). All study participants received oral rifabutin-substituted standard tuberculosis treatment for 180 days. Patients and clinicians were not masked to treatment assignment. Spirometry and sputum culture with solid and liquid media were done at baseline and up to 180 days at specified intervals throughout treatment. The primary endpoint was safety and tolerability up to day 210. Secondary preliminary efficacy endpoints were treatment effects on sputum microbiology (culture status at day 56 and the hazard ratio for stable culture conversion up to day 180) and lung function (FEV1 and forced vital capacity [FVC]) measured by spirometry at day 56, day 180, and day 540. Safety was analysed in the intention-to-treat population and preliminary efficacy primarily in the per-protocol population. The trial is registered at ClinicalTrials.gov, NCT02968927. Post-treatment follow-up was completed in 2020. FINDINGS: Between Nov 18, 2016, and Sept 27, 2018, 200 patients were screened and randomly assigned to different treatment groups (n=40 per group, apart from n=39 in the everolimus group after one patient withdrew consent). 11 treatment-emergent serious adverse events occurred either during treatment or within 30 days after treatment discontinuation, of which three were attributable to a host-directed treatment. Life-threatening thrombocytopenia occurred in an auranofin recipient; apparent intra-abdominal sepsis leading to death occurred in another auranofin recipient and was classified as a suspected unexpected serious adverse reaction. Tuberculous spondylitis occurred as an apparent paradoxical reaction in a patient receiving ergocalciferol. Two patients in the control group had life-threatening, treatment-attributable liver injury. No treatment-emergent, treatment-attributable serious adverse events occurred in patients receiving CC-11050 or everolimus. Mean FEV1 in the control group was 61·7% of predicted (95% CI 56·3-67·1) at baseline and 69·1% (62·3-75·8) at day 180. Patients treated with CC-11050 and everolimus had increased recovery of FEV1 at day 180 relative to the control group (mean difference from control group 6·30%, 95% CI 0·06-12·54; p=0·048; and 6·56%, 0·18-12·95; p=0·044, respectively), whereas auranofin and ergocalciferol recipients did not. None of the treatments had an effect on FVC during 180 days of follow-up or on measures of sputum culture status over the course of the study. INTERPRETATION: CC-11050 and everolimus were safe and reasonably well tolerated as adjunctive therapies for tuberculosis, and analysis of preliminary efficacy suggests they might also enhance the recovery of FEV1, a key measure of lung function and predictor of all-cause mortality. Further studies of these candidates are warranted. FUNDING: The Bill & Melinda Gates Foundation and the South African Medical Research Council.


Subject(s)
Antitubercular Agents/administration & dosage , Auranofin/administration & dosage , Ergocalciferols/administration & dosage , Everolimus/administration & dosage , Indoles/administration & dosage , Phosphodiesterase 4 Inhibitors/administration & dosage , Sulfones/administration & dosage , Tuberculosis, Pulmonary/drug therapy , Adult , Antitubercular Agents/adverse effects , Auranofin/adverse effects , Auranofin/pharmacology , Double-Blind Method , Drug Therapy, Combination , Ergocalciferols/adverse effects , Ergocalciferols/pharmacology , Everolimus/adverse effects , Everolimus/pharmacology , Female , Forced Expiratory Volume/drug effects , Humans , Indoles/adverse effects , Indoles/pharmacology , Male , Middle Aged , Mycobacterium tuberculosis , Phosphodiesterase 4 Inhibitors/adverse effects , Phosphodiesterase 4 Inhibitors/pharmacology , Prospective Studies , South Africa , Sputum/drug effects , Sputum/microbiology , Sulfones/adverse effects , Sulfones/pharmacology
8.
Sex Transm Infect ; 97(4): 249-255, 2021 06.
Article in English | MEDLINE | ID: mdl-33208512

ABSTRACT

OBJECTIVES: Reproductive aged women are at risk of pregnancy and sexually transmitted infections (STI). Understanding drivers of STI acquisition, including any association with widely used contraceptives, could help us to reduce STI prevalence and comorbidities. We compared the risk of STI among women randomised to three contraceptive methods. METHODS: We conducted a secondary analysis to assess the risk of chlamydia and gonorrhoea in a clinical trial evaluating HIV risk among 7829 women aged 16-35 randomised to intramuscular depot medroxyprogesterone acetate (DMPA-IM), a copper intrauterine device (IUD) or a levonorgestrel (LNG) implant. We estimated chlamydia and gonorrhoea prevalences by contraceptive group and prevalence ratios (PR) using log-binomial regression. RESULTS: At baseline, chlamydia and gonorrhoea prevalences were 18% and 5%, respectively. Final visit chlamydia prevalence did not differ significantly between DMPA-IM and copper IUD groups or between copper IUD and LNG implant groups. The DMPA-IM group had significantly lower risk of chlamydia compared with the LNG implant group (PR 0.83, 95% CI 0.72 to 0.95). Final visit gonorrhoea prevalence differed significantly only between the DMPA-IM and the copper IUD groups (PR 0.67, 95% CI 0.52 to 0.87). CONCLUSIONS: The findings suggest that chlamydia and gonorrhoea risk may vary with contraceptive method use. Further investigation is warranted to better understand the mechanisms of chlamydia and gonorrhoea susceptibility in the context of contraceptive use.


Subject(s)
Chlamydia Infections/epidemiology , Contraception/methods , Contraceptive Agents, Female/administration & dosage , Gonorrhea/epidemiology , Intrauterine Devices, Copper , Levonorgestrel/administration & dosage , Medroxyprogesterone Acetate/administration & dosage , Adolescent , Adult , Africa/epidemiology , Delayed-Action Preparations , Disease Susceptibility , Drug Implants , Female , Humans , Prevalence , Young Adult
9.
Lancet HIV ; 7(6): e401-e409, 2020 06.
Article in English | MEDLINE | ID: mdl-32240629

ABSTRACT

BACKGROUND: Short-course preventive therapy with 12 doses of once-weekly rifapentine (900 mg) plus isoniazid (900 mg) could greatly improve tuberculosis control, especially in areas with high co-endemicity with HIV. However, a small previous trial of such therapy with dolutegravir in healthy, HIV-negative adults was halted early after two of the four patients developed serious adverse events. Because of the potential use of this therapy, and variable safety outcomes of tuberculosis drugs seen in patients with and without HIV, we aimed to characterise safety, pharmacokinetics, and virological suppression in adults who are HIV positive. METHODS: DOLPHIN was a phase 1/2, single-arm trial done at The Aurum Institute (Tembisa Clinical Research Site, Tembisa, South Africa), with pharmacokinetic visits done at VxPharma (Pretoria, South Africa). Adults (≥18 years) with HIV infection and undetectable viral load (<40 copies per mL) after at least 8 weeks of efavirenz-based or dolutegravir-based regimens were recruited in three consecutive groups, subject to approval by the independent safety monitoring committee. Participants received 50 mg of daily dolutegravir in place of efavirenz for 8 weeks, then began once-weekly rifapentine (900 mg)-isoniazid (900 mg) for 12 weeks. Groups 1A (n=12) and 1B (n=18) had intensive dolutegravir pharmacokinetic sampling at week 8 (before rifapentine-isoniazid), at week 11 (after the third dose of rifapentine)-isoniazid and at week 16 after the eighth dose. Group 2 (n=30) were treated with the same schedule and had sparse dolutegravir pharmacokinetic sampling at weeks 8, 11, and 16. Participants were followed 4 weeks after completion of prophylactic tuberculosis treatment. HIV viral loads were measured at baseline and at weeks 11 and 24. Primary endpoints were adverse events (grade 3 or higher) and dolutegravir population pharmacokinetics, assessed in participants who began rifapentine-isoniazid. This trial was registered at ClinicalTrials.gov, NCT03435146. FINDINGS: Between Jan 24, 2018, and Nov 25, 2018, 61 participants were enrolled into three groups; one participant withdrew (from group 1A). 43 (70%) of 60 participants were women and all participants were black African. Median age was 40 years (IQR 35-48), CD4 cell count was 683 cells per µL (447-935), and body-mass index was 28·9 kg/m2 (24·0-32·9). Three grade 3 adverse events occurred; two elevated creatinine and one hypertension. Rifapentine-isoniazid increased dolutegravir clearance by 36% (relative standard error 13%) resulting in a 26% decrease in dolutegravir area under the curve. Overall geometric mean ratio of trough concentrations with versus without rifapentine-isoniazid was 0·53 (90% CI 0·49-0·56) though this ratio varied by day after rifapentine-isoniazid dose. All but one trough value was above the 90% maximal inhibitory concentration for dolutegravir and HIV viral loads were less than 40 copies per mL in all patients. INTERPRETATION: Our results suggest 12 doses of once-weekly rifapentine-isoniazid can be given for tuberculosis prophylaxis to patients with HIV taking dolutegravir-based antiretroviral therapy, without dose adjustments. Further exploration of the pharmacokinetics, safety, and efficacy in children and pharmacodynamics in individuals naive to antiretroviral therapy is needed. FUNDING: UNITAID.


Subject(s)
HIV Infections/drug therapy , Heterocyclic Compounds, 3-Ring/administration & dosage , Isoniazid/administration & dosage , Rifampin/analogs & derivatives , Tuberculosis/prevention & control , Adult , Drug Administration Schedule , Female , HIV Infections/virology , HIV-1/genetics , Heterocyclic Compounds, 3-Ring/adverse effects , Humans , Isoniazid/adverse effects , Male , Middle Aged , Oxazines , Piperazines , Pyridones , Rifampin/administration & dosage , Rifampin/adverse effects , South Africa , Treatment Outcome , Viral Load
10.
J Infect Dis ; 220(3): 432-441, 2019 07 02.
Article in English | MEDLINE | ID: mdl-30938435

ABSTRACT

Few human immunodeficiency virus (HIV)-infected persons can maintain low viral levels without therapeutic intervention. We evaluate predictors of spontaneous control of the viral load (hereafter, "viral control") in a prospective cohort of African adults shortly after HIV infection. Viral control was defined as ≥2 consecutively measured viral loads (VLs) of ≤10 000 copies/mL after the estimated date of infection, followed by at least 4 subsequent measurements for which the VL in at least 75% was ≤10 000 copies/mL in the absence of ART. Multivariable logistic regression characterized predictors of viral control. Of 590 eligible volunteers, 107 (18.1%) experienced viral control, of whom 25 (4.2%) maintained a VL of 51-2000 copies/mL, and 5 (0.8%) sustained a VL of ≤50 copies/mL. The median ART-free follow-up time was 3.3 years (range, 0.3-9.7 years). Factors independently associated with control were HIV-1 subtype A (reference, subtype C; adjusted odds ratio [aOR], 2.1 [95% confidence interval {CI}, 1.3-3.5]), female sex (reference, male sex; aOR, 1.8 [95% CI, 1.1-2.8]), and having HLA class I variant allele B*57 (reference, not having this allele; aOR, 1.9 [95% CI, 1.0-3.6]) in a multivariable model that also controlled for age at the time of infection and baseline CD4+ T-cell count. We observed strong associations between infecting HIV-1 subtype, HLA type, and sex on viral control in this cohort. HIV-1 subtype is important to consider when testing and designing new therapeutic and prevention technologies, including vaccines.

11.
Epidemiology ; 28(2): 224-232, 2017 03.
Article in English | MEDLINE | ID: mdl-27893488

ABSTRACT

BACKGROUND: Understanding associations between pregnancy and HIV disease progression is critical to provide appropriate counseling and care to HIV-positive women. METHODS: From 2006 to 2011, women less than age 40 with incident HIV infection were enrolled in an early HIV infection cohort in Kenya, Rwanda, South Africa, Uganda, and Zambia. Time-dependent Cox models evaluated associations between pregnancy and HIV disease progression. Clinical progression was defined as a single CD4 measurement <200 cells/µl, percent CD4 <14%, or category C event, with censoring at antiretroviral (ART) initiation for reasons other than prevention of mother-to-child transmission (PMTCT). Immunologic progression was defined as two consecutive CD4s ≤350 cells/µl or a single CD4 ≤350 cells/µl followed by non-PMTCT ART initiation. Generalized estimating equations assessed changes in CD4 before and after pregnancy. RESULTS: Among 222 women, 63 experienced clinical progression during 783.5 person-years at risk (8.0/100). Among 205 women, 87 experienced immunologic progression during 680.1 person-years at risk (12.8/100). The association between pregnancy and clinical progression was adjusted hazard ratio [aHR] = 0.7; 95% confidence interval (CI): 0.2, 1.8. The association between pregnancy and immunologic progression was aHR = 1.7; 95% CI: 0.9, 3.3. Models controlled for age; human leukocyte antigen alleles A*03:01, B*45, B*57; CD4 set point; and HIV-1 subtype. CD4 measurements before versus after pregnancies were not different. CONCLUSIONS: In this cohort, pregnancy was not associated with increased clinical or immunologic HIV progression. Similarly, we did not observe meaningful deleterious associations of pregnancy with CD4s. Our findings suggest that HIV-positive women may become pregnant without harmful health effects occurring during the pregnancy. Evaluation of longer-term impact of pregnancy on progression is warranted.


Subject(s)
HIV Infections/immunology , Pregnancy Complications, Infectious/immunology , Adult , Anti-HIV Agents/therapeutic use , Antiretroviral Therapy, Highly Active , CD4 Lymphocyte Count , Cohort Studies , Disease Progression , Female , HIV Infections/drug therapy , Humans , Infectious Disease Transmission, Vertical/prevention & control , Kenya , Pregnancy , Pregnancy Complications, Infectious/drug therapy , Proportional Hazards Models , Rwanda , South Africa , Uganda , Zambia
12.
AIDS ; 27 Suppl 1: S17-25, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24088680

ABSTRACT

OBJECTIVE: To evaluate the effect of nevirapine-containing antiretroviral therapy (ART) on combined oral contraceptive (COC) effectiveness. DESIGN: Nonrandomized prospective clinical trial. METHODS: We enrolled HIV-infected women aged 18-35 years in South Africa and Uganda who had regular menses, were sexually active, and had no medical contraindications to COC use. We enrolled 196 women taking nevirapine-containing ART and 206 women not yet eligible for ART as a control group. We treated all participants with low-dose COCs. Our main outcomes were ovulation and pregnancy rates. We estimated ovulation in the first two cycles using weekly serum progesterone and tested for pregnancy monthly for 24 weeks. RESULTS: The median age of participants was 29 and their median CD4 cell count was 486. In the ART group, 43 of 168 (26%) ovulated in cycle 1, 30 of 163 (18%) in cycle 2, and 18 of 163 (11%) in both cycles. In the non-ART group, 26 of 168 (16%) ovulated in cycle 1, 31 of 165 (19%) in cycle 2, and 20 of 165 (12%) in both cycles. We found no significant difference in ovulation rates between groups: unadjusted odds ratio 1.36 (95% confidence interval 0.85-2.18). Pregnancy rates also did not differ: 10.0 per 100-women-years in the ART group and 10.1 per 100-women-years in the non-ART group. Self-reported COC adherence, condom use, vaginal bleeding, and adverse events were similar. Five serious adverse events were reported, all in the non-ART group. CONCLUSION: ART use did not affect risk of ovulation or pregnancy in women taking COCs, suggesting that nevirapine-containing ART does not interfere with COC contraceptive effectiveness.


Subject(s)
Anti-HIV Agents/administration & dosage , Antiretroviral Therapy, Highly Active/methods , Contraceptives, Oral/pharmacology , Contraceptives, Oral/pharmacokinetics , Drug Interactions , HIV Infections/drug therapy , Nevirapine/administration & dosage , Adolescent , Adult , Female , Humans , Ovulation/drug effects , Pregnancy , Prospective Studies , South Africa , Uganda , Young Adult
13.
Syst Appl Microbiol ; 28(6): 527-40, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16104351

ABSTRACT

Traditional fermentation of cassava is dominated by a lactic acid bacteria (LAB) population. Fermentation is important for improving product flavour and aroma as well as safety, especially by reduction of its toxic cyanogenic glucosides. The production of Gari from cassava in Benin typically occurs on a household or small industrial scale, and consequently suffers from inconsistent product quality and may not always be safe for consumption. Therefore, the diversity of LAB from a typical cassava fermentation for the preparation of Gari, and their technologically relevant characteristics were investigated with a view towards selection of appropriate starter cultures. A total of 139 predominant strains isolated from fermenting cassava were identified using phenotypic tests and genotypic methods such as rep-PCR and RAPD-PCR. DNA-DNA hybridisation and sequencing of the 16S rRNA genes were done for selected strains. Lactobacillus plantarum was the most abundantly isolated species (54.6% of isolates), followed by Leuconostoc fallax (22.3%) and Lactobacillus fermentum (18.0%). Lactobacillus brevis, Leuconostoc pseudomesenteroides and Weissella paramesenteroides were sporadically isolated. The L. plantarum strains were shown to be better acid producers and capable of faster acid production than the L. fallax or L. fermentum strains. The incidence of beta-glucosidase (linamarase) activity was also highest among strains of this species. Production of antagonistic substances such as H2O2 and bacteriocins, however, was more common among L. fallax and L. fermentum strains. Strains of all three species were capable of utilising the indigestible sugars raffinose and stachyose. Therefore, a starter culture containing a mixture of strains from all three species was recommended.


Subject(s)
Food Microbiology , Lactobacillus plantarum/classification , Lactobacillus/classification , Leuconostoc/classification , Manihot/microbiology , Benin , DNA, Ribosomal/analysis , Fermentation , Genes, rRNA , Genotype , Lactobacillus/genetics , Lactobacillus/isolation & purification , Lactobacillus/metabolism , Lactobacillus plantarum/genetics , Lactobacillus plantarum/isolation & purification , Lactobacillus plantarum/metabolism , Leuconostoc/genetics , Leuconostoc/isolation & purification , Manihot/metabolism , Molecular Sequence Data , Nucleic Acid Hybridization , Phenotype , RNA, Ribosomal, 16S/genetics , Random Amplified Polymorphic DNA Technique , Sequence Analysis, DNA
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