Faculty of Health Sciences (Research Outputs)

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End date: 2019Subject: search.filters.subject.SDG-17: Partnerships for the goals

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Now showing 1 - 5 of 5
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    Performance of the Biomark HD real-time qPCR System (Fluidigm) for the detection of nasopharyngeal bacterial pathogens and Streptococcus pneumoniae typing
    (Nature Research, 2019-04) Olwagen, Courtney P.; Adrian, Peter V.; Madhi, Shabir A.
    Traditional qPCR assays for pneumococcal detection and serotype characterization require large sample volume, is expensive and labor intensive. We aimed to develop a quantitative nanofuidic Fluidigm assay to overcome some of these shortcomings. A quantitative Fluidigm assay was established to detect 11 bacterial pathogens, 55 pneumococcal serotypes and 6 serotypes of H. infuenzae. The Fluidigm assay results were compared to conventional qPCR and culture. All reactions in the Fluidigm assay efectively amplifed their respective targets with high sensitivity and specifcity compared to qPCR. There was excellent concordance between qPCR and Fluidigm for detection of carriage prevalence (kappa>0.75) and density (Rho>0.95). Fluidigm identifed an additional 7 (4.2%) serotypes over those detected by qPCR. There was a modest concordance between culture and Fluidigm for the majority of reactions detecting S. pneumoniae serotypes/serogroups (kappa>0.6), with Fluidigm identifying an additional 113 (39.1%) serotypes. Discordant results between the three methods were associated with a low carriage density. The Fluidigm assay was able to detect common pneumococcal serotypes, H. infuenzae serotypes, and other common nasopharyngeal bacterial organisms simultaneously. Deployment of this assay in epidemiological studies could provide better insight into the efect of PCV immunization on the nasopharyngeal microbiota in the community
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    Characterization of putative DD-carboxypeptidase-encoding genes in Mycobacterium smegmatis
    (Nature Research, 2019-03) Ealand, Christopher S.; Asmal, Rukaya; Mashigo, Lethabo; Campbell, Lisa; Kana, Bavesh D.
    Penicillin binding proteins (PBPs) are the target of numerous antimicrobial agents that disrupt bacterial cell wall synthesis. In mycobacteria, cell elongation occurs through insertion of nascent cell wall material in the sub-polar region, a process largely driven by High Molecular Weight PBPs. In contrast, the function of DD-carboxypeptidases (DD-CPases), which are Low Molecular Weight Class 1C PBPs, in mycobacteria remains poorly understood. Mycobacterium smegmatis encodes four putative DD-CPase homologues, which display homology to counterparts in Escherichia coli. Herein, we demonstrate that these are expressed in varying abundance during growth. Deletion of MSMEG_1661, MSMEG_2433 or MSMEG_2432, individually resulted in no defects in growth, cell morphology, drug susceptibility or spatial incorporation of new peptidoglycan. In contrast, deletion of MSMEG_6113 (dacB) was only possible in a merodiploid strain expressing the homologous M. tuberculosis operon encoding Rv3627c (dacB), Rv3626c, Rv3625c (mesJ) and Rv3624c (hpt), suggestive of essentiality. To investigate the role of this operon in mycobacterial growth, we depleted gene expression using anhydrotetracyclineresponsive repressors and noted reduced bipolar peptidoglycan synthesis. These data point to a possible role for this four gene operon, which is highly conserved across all mycobacterial species, in regulating spatial localization of peptidoglycan synthesis.
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    Assessing runs of Homozygosity: a comparison of SNP Array and whole genome sequence low coverage data
    (BMC, 2018-01) Ceballos, Francisco C.; Hazelhurst, Scott; Ramsay, Michèle
    Background: Runs of Homozygosity (ROH) are genomic regions where identical haplotypes are inherited from each parent. Since their first detection due to technological advances in the late 1990s, ROHs have been shedding light on human population history and deciphering the genetic basis of monogenic and complex traits and diseases. ROH studies have predominantly exploited SNP array data, but are gradually moving to whole genome sequence (WGS) data as it becomes available. WGS data, covering more genetic variability, can add value to ROH studies, but require additional considerations during analysis. Results: Using SNP array and low coverage WGS data from 1885 individuals from 20 world populations, our aims were to compare ROH from the two datasets and to establish software conditions to get comparable results, thus providing guidelines for combining disparate datasets in joint ROH analyses. By allowing heterozygous SNPs per window, using the PLINK homozygosity function and non-parametric analysis, we were able to obtain non-significant differences in number ROH, mean ROH size and total sum of ROH between data sets using the different technologies for almost all populations. Conclusions: By allowing 3 heterozygous SNPs per ROH when dealing with WGS low coverage data, it is possible to establish meaningful comparisons between data using SNP array and WGS low coverage technologies
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    Cash transfer interventions for sexual health: meanings and experiences of adolescent males and females in inner-city Johannesburg
    (BMC, 2018) Khoza, Nomhle; Stadler, Jonathan; MacPhail, Catherine; Chikandiwa, Admire; Brahmbhatt, Heena; Delany-Moretlwe, Sinead
    Background: In sub-Saharan Africa, there is growing interest in the use of cash transfer (CT) programs for HIV treatment and prevention. However, there is limited evidence of the consequences related to CT provision to adolescents in low-resourced urban settings. We explored the experiences of adolescents receiving CTs to assess the acceptability and unintended consequences of CT strategies in urban Johannesburg, South Africa. Methods: We collected qualitative data during a pilot randomized controlled trial of three CT strategies (monthly payments unconditional vs. conditional on school attendance vs. a once-off payment conditional on a clinic visit) involving 120 adolescents aged 16–18 years old in the inner city of Johannesburg. Interviews were conducted in isiZulu, Sesotho or English with a sub-sample of 49 participants who adhered to study conditions, 6 months after receiving CT (280 ZAR/ 20 USD) and up to 12 months after the program had ended. Interviews were transcribed and translated by three fieldworkers. Codes were generated using an inductive approach; transcripts were initially coded based on emerging issues and subsequently coded deductively using Atlas.ti 7.4. Results: CTs promoted a sense of independence and an adult social identity amongst recipients. CTs were used to purchase personal and household items; however, there were gender differences in spending and saving behaviours. Male participants’ spending reflected their preoccupation with maintaining a public social status through which they asserted an image of the responsible adult. In contrast, female participants’ expenditure reflected assumption of domestic responsibilities and independence from older men, with the latter highlighting CTs’ potential to reduce transactional sexual partnerships. Cash benefits were short-lived, as adolescents reverted to previous behavior after the program’s cessation. Conclusion: CT programs offer adolescent males and females in low-income urban settings a sense of agency, which is vital for their transition to adulthood. However, gender differences in the expenditure of CTs and the effects of ending CT programs must be noted, as these may present potential unintended risks.
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    Social health insurance contributes to universal coverage in South Africa, but generates inequities: survey among members of a government employee insurance scheme
    (BMC, 2018) Goudge, Jane; Harris, Bronwyn; Nxumalo, Nonhlanhla; Chersich, Matthew F.; Alaba, Olufunke A.; Govender, Veloshnee
    Background: Many low- and middle-income countries are reforming their health financing mechanisms as part of broader strategies to achieve universal health coverage (UHC). Voluntary social health insurance, despite evidence of resulting inequities, is attractive to policy makers as it generates additional funds for health, and provides access to a greater range of benefits for the formally employed. The South African government introduced a voluntary health insurance scheme (GEMS) for government employees in 2005 with the aim of improving access to care and extending health coverage. In this paper we ask whether the new scheme has assisted in efforts to move towards UHC. Methods: Using a cross-sectional survey across four of South Africa’s nine provinces, we interviewed 1329 government employees, from the education and health sectors. Data were collected on socio-demographics, insurance coverage, health status and utilisation of health care. Multivariate logistic regression was used to determine if service utilisation was associated with insurance status. Results: A quarter of respondents remained uninsured, even higher among 20–29 year olds (46%) and lower-skilled employees (58%). In multivariate analysis, the odds of an outpatient visit and hospital admission for the uninsured was 0.3 fold that of the insured. Cross-subsidisation within the scheme has provided lower-paid civil servants with improved access to outpatient care at private facilities and chronic medication, where their outpatient (0.54 visits/ month) and inpatient utilisation (10.1%/year) approximates that of the overall population (29.4/month and 12.2% respectively). The scheme, however, generated inequities in utilisation among its members due to its differential benefit packages, with, for example, those with the most benefits having 1.0 outpatient visits/month compared to 0.6/ month with lowest benefits. Conclusions: By introducing the scheme, the government chose to prioritise access to private sector care for government employees, over improving the availability and quality of public sector services available to all. Government has recently regained its focus on achieving UHC through the public system, but is unlikely to discontinue GEMS, which is now firmly established. The inequities generated by the scheme have thus been institutionalised within the country’s financing system, and warrant attention. Raising scheme uptake and reducing differentials between benefit packages will ameliorate inequities within civil servants, but not across the country as a whole.