Abstract available in the Journal of Investigative Medicine.

The changes occurring in the red blood cells in infective illness are amongst the least carefully studied problems of haematology. In spite of the fact that these anamias are extremely common, it is difficult to find adequate literature to make possible even a clear description of the blood picture under these circumstances. Part of the difficulty is due to the fact that anaemias in infections are grouped together with other anaemia, in which many mechanisms undoubtedly active. Another major source of confusion is the fact that in many of the cases in which "secondary anaemia" occurs, complicating factors such as haemorrhage and liver disease are not adequately dealt with.

The phytochemical investigation of an ethanol extract of Artemisia afra, led to the isolation of six known compounds, Acacetin (1) 12α,4α-dihydroxybishopsolicepolide (2), Scopoletin (3) α-amyrin (4), Phytol (5) and a pentacyclic tri-terpenoid Betulinic acid (6). The isolated compounds were evaluated for their anti-microbial activity against Gram positive (Actinomyces naeslundii, Actinomyces israelii and Streptococcus mutans), Gram negative bacteria (Privotella intermedia, Porphyromonus gingivalis and Aggregatibacter actinomycetemcomitans previously known as Actinobacillus actinomycetemcomitans) and Candida albicans. The crude extract of A. afra inhibited the growth of all tested microbial species at concentration range of 1.6 mg/ml to 25.0 mg/ml. The compounds 1-6 also showed activity range at 1.0 mg/ml to 0.25 mg/ml. Three best compounds which showed good activity were selected for further studies. Cytotoxicity of the extract and compounds was determined using the XTT (Sodium 3’-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate) cell proliferation kit. The antioxidant activity of the extract and compounds was done using the DPPH scavenging method. The extract showed good antioxidant activity with an IC50 value of 22.2 μg/ml. Scopoletin had a strong transformation of the DPPH radical into its reduced form, with an IC50 value of 1.24 μg/ml which was significant to that of vitamin C (1.22 μg/ml). Acacetin and Betulinic acid exhibited a decreased scavenging activity with the IC50 of 2.39 and 2.42 _g/ml, respectively. The extract and compounds showed moderate toxicity on McCoy fibroblast cell line and the extract influenced the release of cytokine against Hep2 cells. Scopoletin was relatively non-toxic with an IC50 value of 132.5 μg/ml. Acacetin and betulinic acid also showed a smooth trend of non-toxic effects at lower concentrations and toxic at higher concentrations with IC50 values of 35.44 and 30.96 μg/ml. The obtained results in this confirmed the use of A. afra in the treatment of microbial infections. / Dissertation (MSc)--University of Pretoria, 2012. / Plant Science / unrestricted

Includes bibliographical references / Background: Tuberculosis (TB) control depends on interrupting transmission through rapid diagnosis and treatment initiation of infectious TB cases. With increasing delay in the diagnosis and treatment of pulmonary TB, disease is likely to progress, leading to progressive lung cavitation and increased sputum bacillary load, likely increasing TB transmission. This study investigated the effect of treatment delay in adult TB patients on the risk of TB infection and disease in child household contacts. Methodology: Secondary analysis was performed using data from a community-based household contact investigation study. Cross-sectional analysis was conducted of baseline data collected at enrolment. Children aged three months to fifteen years with documented household exposure to an adult with TB were enrolled between December 2007 and June 2012. These children were screened for TB infection (Mantoux tuberculin skin test [TST] and two interferon-gamma release assays [IGRA]) and disease. Total treatment delay was measured in adult TB source cases as the time from cough onset until treatment initiation, with those reporting no cough serving as the reference category. Logistic regression models were used to evaluate the effect of total treatment delay in adults on the risk of TB infection in child household contacts, with TB disease evaluated as a secondary endpoint. Results In total 671 children were enrolled as household contacts of 290 adult TB source cases. In multivariate analysis, the odds of TST positivity increased with cough duration ≥4 weeks prior to TB treatment initiation (odds ratio (OR) = 1.77 [95% CI 1.02-3.09] for cough <4 weeks; OR = 2.74 [95% confidence interval ( CI ) = 1.39-5.40] for cough 4-12 weeks; OR = 2.39 [95% CI = 1.19-4.82] for cough >12 weeks, compared to non-coughing adult TB patients), child's age ≥5 years (OR = 4.51, [95% CI = 2.60-7.83]), sharing the same bedroom (OR = 2.17, [95% CI = 1.43-3.31]), more than one household TB contact (OR = 2.70, [95% CI = 1.35- 2 5.42]) and with household tobacco smoke exposure (OR = 2.10, [95% CI = 1.22-3.61]). Adult TB source case HIV status did not modify the association between cough duration and risk of infection in children. Results of analyses of TB infection indicated by IGRA positivity were consistent with TST results. Prevalent TB disease in child contacts was associated with source case sputum smear and culture positivity, additional household TB contacts and decreasing age of the child. Conclusions: Delays of longer than four weeks from cough onset until TB treatment initiation were associated with increased risk of TB infection in child household contacts. These findings confirm the importance of reducing delays in TB diagnosis and treatment in adults to reduce transmission, ideally to less than four weeks. Although HIV co -infected TB patients are often considered less infectious, delayed treatment initiation remained associated with TB transmission, even amongst HIV co-infected adults with TB. In addition to the traditional risk factors for developing TB disease after infection, source case exposure factors also increased the risk of exposed children developing TB disease.

No description available.

Background: HIV transmission is greatly reduced when antiretroviral treatment (ART) suppresses an infected person’s HIV viral load. It is unclear, however, whether the contextual risk of incident HIV is optimally reduced by widespread individual-level suppression of HIV viral load alone or in combination with other HIV prevention services. HIV service coverage and community norms can influence risk in small area geographies; and contextual factors, like gender inequality and stigma, may foster environments conducive to HIV transmission. Yet, the relationship between places with high HIV levels and the clustering of area risk factors is unknown. The goal of this dissertation is to learn if and how a geographically focused combination implementation strategy could reduce population-level HIV risk. Analyses explored whether small area risk profiles explain area differences in HIV. The guiding hypothesis is that in high HIV prevalence settings, low HIV service uptake in a geographically defined area increases the prevalence of high HIV viremia, leading to greater HIV transmission and incident HIV. Methods: A systematic review was conducted to examine the association between population-level measures of HIV viral load and incident HIV infection in generalized and concentrated epidemics. Publications were English, peer-reviewed articles published from January 1, 1995 through February 15, 2019 that explicitly defined HIV viral load and assessed outcomes of HIV recency, incidence, seroconversion, or new diagnosis. Studies sampled general or key populations through population-based surveillance registries, household-based enumeration, cluster sampling, or respondent driven sampling. Descriptive statistics summarized review findings. The Swaziland HIV Incidence Measurement Survey (SHIMS) data were used for the remaining analyses. Using a two-stage cluster-based design, a nationally representative, household-based sample of adults, ages 18-49 years was enrolled from December 2010 to June 2011 in Eswatini. Consenting adults completed an interview and received home-based rapid HIV testing and counseling. All seropositive samples were tested for HIV viral load using the COBAS AmpliPrep/Taqman HIV-1 Test, v 2.0. Adults testing HIV-seronegative were enrolled in a prospective cohort for the direct observation of HIV seroconversion, completing an interview and home-based rapid HIV testing six months later. Multi-level latent class modeling was performed to identify statistically significant combinations of HIV risk factors and to classify the combinations into small area risk profiles. In the cross-sectional sample, linear regression with robust standard errors assessed the correlation between area profiles and places with high levels of uncontrolled HIV infection, or HIV core areas, measured by the area prevalence of detectable virus (≥20 copies/milliliter) among HIV-positive adults and among all adults, regardless of HIV status. In the prospective cohort, generalized linear regression of longitudinal data assessed the association between area profiles and places prone to new HIV infections (i.e., HIV susceptible areas), measured by area-level HIV seroconversions. Results: The systematic review found an evidence base primarily of lower quality studies and inconsistent HIV viral exposure measurement. Overall findings supported a relationship between increasing levels of suppressed HIV in HIV-infected populations and fewer new infections over time. Better quality studies consistently showed higher population viremia (i.e. HIV viral quantity among all persons, regardless of HIV status) associated with HIV incidence in high prevalence populations; population viral load (i.e., HIV viral quantity among only HIV-positive persons) did not show an association with incident HIV in high prevalence, general populations and was inconsistent in key populations. To determine whether area risk profiles can pinpoint HIV core areas, latent class modeling was used to categorize 18,172 adults into one of six HIV risk types. The risk typology, classified through unique combinations of HIV service uptake and sexual risk behaviors, conveyed an adult’s propensity for HIV transmission and/or acquisition risk. The model next identified the area-level composite prevalences of HIV risk types; estimated the three most frequent, unique composite combinations; and categorized them into area risk profiles characterizing HIV risk: low-moderate acquisition risk, moderate acquisition/transmission risk, and high acquisition/transmission risk. The high acquisition/transmission areas comprised the largest proportions of highest risk transmission and acquisition types. The prevalence of detectable viremia progressively increased from low-moderate acquisition, moderate acquisition/transmission, and high acquisition/transmission profiles [17.7%, 25.4%, and 35.1%, respectively]. When compared with low-moderate acquisition areas, the prevalence of detectable viremia was 7.4% [p<.001] higher in moderate acquisition/transmission areas and 17.1% [p<.001] higher in high acquisition/transmission areas. The prevalence of detectable viral load significantly decreased from low-moderate acquisition to moderate acquisition/transmission areas [76.6% versus 68.7%, p<.001], and was significantly higher in high acquisition/transmission areas by 7.3% [p<.001], when compared with low-moderate acquisition areas. To determine whether area risk profiles can predict HIV susceptible areas, a total of 18,172 adults were surveyed of which 4396 [24%] had detectable viremia. 11,880 [96%; n=12,357] HIV-seronegative adults enrolled in the prospective cohort and 11,155 [94%] of them completed an endline visit. Four area profiles were identified, defined by unique patterns in prevalence of HIV viremia and of sexual risk behaviors. The proportion of HIV susceptible areas progressively increased from Profiles A, B, C, and D [14.3%, 21.8%, 24.6%, and 30.8%, respectively]. HIV susceptible areas were more than twice as likely to occur in Profile D than Profile A environments [RR 2.13, 95% confidence interval (CI) (1.13, 4.00); p=0.02]. Profile D areas had prevalences of unknown partner HIV status and detectable viremia at 28% and 24%, respectively. In contrast, Profile A areas had prevalences of only 8% with unknown HIV status and 31% with detectable viremia. Conclusion: This dissertation shows that geographic risk profiles can explain differences in population-level HIV outcomes. Risk factors spatially cluster in predictable, meaningful combinations that can inform an area typology of HIV risk. The co-location of adults predisposed to greater HIV risk may heighten levels of uncontrolled HIV infection, thereby creating potential area sources of ongoing transmission; however, the concurrent levels of other risk factors may have more influence in reducing population-level incidence than previously considered. A composite indicator of contextual HIV risk may reveal places core to HIV transmission and susceptible to HIV acquisition. Such area profiles may help identify the combination of locally specific risk factors that readily promulgate HIV and better inform the design of place-based HIV intervention packages to enhance current strategies towards global HIV control.

A Dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Medicine in Otorhinolaryngology, Johannesburg, 2018 / This study is a seven year (01/07/08 - 30/06/15) retrospective review of the microbiology of deep neck infections in 52 adult patients at Chris Hani Baragwanath academic hospital. Micro-organisms isolated from patients with deep neck infections were analysed, including their antibiotic susceptibility patterns. The effectiveness of empiric usage of amoxicillin – clavulanic acid against commonly identified microbes and recommended alternative antibiotic usage were reviewed.The register records of 70 microscopy, culture, and antibiotic sensitivity results of specimens taken intraoperatively, in patients with deep neck infections who underwent surgical intervention, were analysed. Aerobic identified gram negative bacilli and streptococcus species; and anaerobic Prevotella, were the most frequently isolated microorganisms. Microbial sensitivity and resistance to amoxicillin – clavulanic acid was reported in 15% (n = 8) of patients with deep neck infections. Hence, the effectiveness of empiric usage of amoxicillin – clavulanic acid, against microbes commonly involved in deep neck infections in adults at Chris Hani Baragwanath academic hospital; cannot be proved nor disproved and is thus recommended as an option; alternative empiric antibiotic usage likewise cannot be recommended. Further periodic surveillance of microbial profiles and associated antimicrobial susceptibility results, in larger population samples of patients with deep neck infections; utilizing standardized protocols, is suggested. / XL2018

MSc (MED) RESEARCH REPORT UNIVERSITY OF THE WITWATERSRAND, JOHANNESBURG. / The research report represents a study to determine the prevalence of antibiotic-resistance of pneumococcal and their scrotypes in Maputo, Mozambique in children under 5 years of age, who were admitted with pneumonia in the Paediatric Unit at the Hospital Central de Maputo. The children included in the study were from suburbs surrounding central Maputo. [Abbreviated Abstract. Open document to view full version] / AC2017

Vibrio cholerae, the etiological agent of the severe diarrheal disease cholera, is an enteric pathogen that can be found in aquatic ecosystems when not colonizing the human gastrointestinal tract. Under adverse environmental conditions, V. cholerae is capable of entering dormant states that increase its survival during these ecological fluctuations. In these states, V. cholerae slows its metabolic activity and exhibits drastically altered gene expression and morphology. Stressors that lead to entry into these states vary from nutrient limitation, suboptimal pH, or antimicrobials. Cells in these dormant states are highly resistant to antimicrobials and cannot be detected using standard microbiological techniques which poses major public health challenges such as food or water contamination. In V. cholerae, proteolysis of virulence regulator ToxR has been identified to be required for entry into a dormant state called viable but nonculturable (VBNC) under nutrient limitation and alkaline pH mediated by the sigma-E stress response. However, the mechanisms that lead to the initiation of this cascade remain unknown. The stringent response is another mechanism involved in mediating bacterial survival during late stationary phase. The stringent response involves the alarmone (p)ppGpp, which acts at the level of transcription to inhibit cellular processes that consume significant resources and activate genes responsible for biosynthetic processes. RelA is one enzyme responsible for the synthesis of (p)ppGpp, which in turn activates transcription of RpoE, suggesting a potential connection with ToxR proteolysis. Therefore, the aim of this study is to define the role of RelA in dormancy and ToxR proteolysis in V. cholerae. Our results show that RelA alone is not sufficient to control dormancy and ToxR proteolysis in V. cholerae. Nonetheless, another regulator (SpoT) is also associated with (p)ppGpp synthesis, indicating that other stringent response-associated mechanisms might be involved in ToxR proteolysis.

The emergence of human pathogens represents a major current global health concern. Characterization of the adaptations required for a given microorganism to emerge as a human pathogen is important for understanding epidemics, as we are typically aware of a pathogen's existence only after it has emerged, manifesting as an outbreak. Cholera is a severe diarrheal disease caused by the aquatic bacterium Vibrio cholerae O1 and is one paradigmatic example of disease emergence. Only a subset of V. cholerae strains can cause the disease while the majority of the strains cannot cause cholera symptoms. We found that toxigenic strains of V. cholerae encode allelic variations of core genes, termed Virulence Adaptive Polymorphisms (VAPs), that confer preadaptations towards the emergence of pathogenic traits. Interestingly, VAPs appear to naturally circulate in environmental populations of V. cholerae. One gene potentially encoding VAPs codes for the outer membrane protein U, OmpU. This major porin plays numerous roles in V. cholerae pathogenesis such as bile tolerance, antimicrobial peptide resistance or facilitates intestinal colonization. Interestingly, we found that these phenotypes appear to be allelic dependent and might provide a clue towards the emergence of toxigenic V. cholerae. To date, the distribution and prevalence of VAPs in environmental populations and the specific molecular mechanisms leading to their virulence preadaptations remain unknown. Here we examined the diversity of ompU alleles in natural V. cholerae populations in order to identify VAPs unique to the toxigenic allele of ompU to discern these preadaptations. We developed a comparative framework to address this by examining allelic variations of OmpU from an endemic population of V. cholerae that we identified for this study in Eastern Florida. We generated 14 isogenic mutant strains each encoding a unique ompU allele that largely covered the landscape of protein variability and examined their resistance profile to host antimicrobials. We determined the genotype to phenotype associations between these mutants and identified and experimentally confirmed four conserved domains that are unique to alleles of ompU that confer resistance to bile and other host antimicrobials. Interestingly, a mutant strain in which we exchanged the four domains of the clinical allele for those of a strain that was sensitive, exhibits a resistance profile closer to an OmpU deletion mutant. Our findings highlight the critical importance of allelic variations in the emergence of virulence adaptive traits and the suitability of our approach towards dissecting its emergence. This tractable approach can be naturally applied to other bacterial pathogens.