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1.
Molecules ; 23(6)2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29844261

RESUMO

The aim of this study was to determine the antioxidant activity of the extractable and non-extractable phenolics of Terminalia. Sericea Burch. Ex DC. Free, ester bound, ether or glycoside bound and insoluble phenolics were extracted from the fruit, leaves, stem, and root samples. Follin Ciocalteu was used to estimate the phenolic content while DPPH (2,2-diphenyl-1-picrylhydrazyl) assay was used to determine the antioxidant activity. The data obtained were subjected to multivariate analysis for relationships. The result indicated that the highest average total phenolic contents and antioxidant activities were found in the free (14.8 mgGAE/g; IC50 6.8 µg/mL) and ester bound (15.1 mgGAE/g; IC50 6.4 µg/mL) extractable phenolics. There was a strong negative correlation between TPC and DPPH (r = -0.828). Agglomerative hierarchical clustering revealed three clusters. Cluster one contained the insoluble and glycoside phenolics while cluster 2 contained only free phenolic acid of the root. The third cluster was predominantly free and ester bound phenolic extracts. The principal component analysis score plot indicated two major clusters with factor 1 (F1) explaining 61% of the variation. The nuclear magnetic resonance spectroscopy spectra indicated that gallic acid and resveratrol are the major phenolic compounds present in the root. This study has demonstrated that extractable phenolics contributed more to the antioxidant activities compared to the non-extractables.


Assuntos
Antioxidantes/química , Extração Líquido-Líquido/métodos , Fenóis/química , Terminalia/química , Antioxidantes/isolamento & purificação , Compostos de Bifenilo/antagonistas & inibidores , Flavonoides/química , Flavonoides/isolamento & purificação , Frutas/química , Ácido Gálico/química , Ácido Gálico/isolamento & purificação , Espectroscopia de Ressonância Magnética , Fenóis/isolamento & purificação , Picratos/antagonistas & inibidores , Extratos Vegetais/química , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , Análise de Componente Principal , Resveratrol , Estilbenos/química , Estilbenos/isolamento & purificação
2.
Molecules ; 22(8)2017 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-28788073

RESUMO

Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function.


Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Plasmodium/efeitos dos fármacos , Pterocarpus/química , Ziziphus/química , Adenosina Trifosfatases/antagonistas & inibidores , Relação Dose-Resposta a Droga , Fenóis/química , Fenóis/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimento , Ligação Proteica , Estabilidade Proteica/efeitos dos fármacos
3.
Trop Med Int Health ; 21(1): 2-17, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26436862

RESUMO

OBJECTIVES: To assess the contribution of Human Norovirus to diarrhoeal diseases in Africa. METHODS: We conducted a systematic review of the PubMed and EMBASE databases for published articles of Human Norovirus in Africa between 1990 and 2013. Data were extracted from selected studies and analysed. RESULTS: A total of 208 eligible studies were identified, of which 55 (from 19 countries) met the inclusion criteria. Many cases were of sporadic gastroenteritis (70.9%) in children (82%), 65.4% of which were seen in an outpatient setting. Over half (59.4%) of the affected children were under 5 years of age. The pooled prevalence rate of Human NoV was 11% (95% CI 8-14%), and the meta-analysis indicated significant heterogeneity between the studies. However, the conditional negative binomial regression could not clearly find the factors affecting the Human NoV prevalence rates reported. A close relationship was found between Human Norovirus strains from environmental and clinical samples. CONCLUSION: Unreported sporadic gastroenteritis cases of Human Norovirus are common in Africa. Most are community-associated infections. Possible environmental transmission routes have been documented. Combined environmental and clinical studies are required for targeted actions to control transmission of Human Norovirus in Africa. Systematic surveillance of Human Norovirus is needed to measure the burden of Norovirus-induced gastroenteritis in Africa and support any requirements for vaccine development.

4.
Health Res Policy Syst ; 12: 68, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25510403

RESUMO

BACKGROUND: Despite its contribution to global disease burden, diarrhoeal disease is still a relatively neglected area for research funding, especially in low-income country settings. The SNOWS consortium (Scientists Networked for Outcomes from Water and Sanitation) is funded by the Wellcome Trust under an initiative to build the necessary research skills in Africa. This paper focuses on the research training needs of the consortium as identified during the first three years of the project. METHODS: We reviewed the reports of two needs assessments. The first was a detailed needs assessment led by one northern partner, with follow-up visits which included reciprocal representation from the African universities. The second assessment, led by another northern partner, focused primarily on training needs. The reports from both needs assessments were read and stated needs were extracted and summarised. RESULTS: Key common issues identified in both assessments were supervisory skills, applications for external research funding, research management, and writing for publication in the peer-reviewed scientific literature. The bureaucratisation of university processes and inconsistencies through administration processes also caused problems. The lack of specialist laboratory equipment presented difficulties, particularly of inaccessibility through a lack of skilled staff for operation and maintenance, and of a budget provision for repairs and running costs. The lack of taught PhD modules and of research training methods also caused problems. Institutionally, there were often no mechanisms for identifying funding opportunities. On the other hand, grantees were often unable to understand or comply with the funders' financial and reporting requirements and were not supported by their institution. Skills in staff recruitment, retention, and performance were poor, as were performance in proposal and paper writing. The requirements for ethical clearance were often not known and governance issues not understood, particularly those required by funders. CONCLUSIONS: SNOWS believes that working with African universities to develop networks that support African-led research driven by the local context is an effective approach to develop and retain research skills needed to change policy and practice in water, sanitation, and hygiene in Africa.


Assuntos
Pesquisa Biomédica/economia , Diarreia/prevenção & controle , Saúde Ambiental/educação , Universidades/organização & administração , África , Currículo , Educação de Pós-Graduação em Medicina/organização & administração , Humanos , Avaliação das Necessidades , Saneamento/normas , Água/normas
5.
Artigo em Inglês | MEDLINE | ID: mdl-25427345

RESUMO

Intestinal parasitic organisms are common pathogens among HIV patients worldwide and have been known to cause severe and life-threatening diarrhea in such subjects. In the present study, the prevalence of Cryptosporidium spp and other intestinal parasites in stool samples from 151 HIV/AIDS patients attending a HIV treatment center in South Africa was determined using' standard parasitological methods, as well as molecular methods including PCR and quantitative PCR for confirmation of Cryptosporidium spp. In addition, the loop-mediated isothermal amplification (LAMP) method was evaluated for detection of Cryptosporidium spp in 24 stool samples. Standard parasitological methods indicated that Cryptospo- ridium spp (26.5%), Entamoeba spp (26.5%) and Giardia lamblia (13%) were the most common protozoan parasites, while Ascaris lumbricoides (8%), Schistosoma mansoni (6%) and Trichuris trichiura (4.6%) were the most commonly found helminths. PCR, quantitative PCR and LAMP methods identified Cryptosporidium spp in 28% (30/106), 35% (53/151) and 58% (14/24) of the stool samples, respectively. Multiple infections (34%) were commonly found in the study population. Females above 45 years had the highest Cryptosporidium prevalence (58%). Prevention measures must be implemented in order to curb the negative impact of Cryptosporidium-causing diarrhea among HIV/AIDS patients in this region as well as other parasitic infections identified in this study.


Assuntos
Cryptosporidium/isolamento & purificação , Infecções por HIV/epidemiologia , Helmintíase/epidemiologia , Enteropatias Parasitárias/epidemiologia , Infecções por Protozoários/epidemiologia , Síndrome da Imunodeficiência Adquirida/epidemiologia , Adolescente , Adulto , Instituições de Assistência Ambulatorial , Criança , Pré-Escolar , Coinfecção , Criptosporidiose/epidemiologia , Fezes/parasitologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prevalência , África do Sul/epidemiologia , Adulto Jovem
6.
Microorganisms ; 12(1)2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38257997

RESUMO

The global spread of cefotaxime-hydrolysing ß-lactamase (CTX-M)-producing Escherichia coli (E. coli) and its associated impact on paediatric diarrhoeal treatment and management has become a public health concern. This review assessed surveillance studies on CTX-M-producing E. coli associated with diarrhoea in children published between 2012 and 2022 globally. A total of thirty-eight studies were included for data analysis, categorised into continental regions, and tabulated. The majority (68%) of studies were conducted in Asian countries while few studies were conducted in Europe (11%) and Africa (18%), respectively. On the African continent, the majority (11%) of studies were conducted in Northern Africa while no studies were reported in East Africa. On the American continent, 3% of the studies were reported from South America. The studies included were classified into diarrheagenic E. coli (74%; 28/38) and faecal carriage (26%; 10/38). Of all the E. coli pathotypes associated with CTX-M production, EPEC was frequently reported. The prevalence of CTX-M-producing E. coli including the CTX-M-15-producing variants ranged between 1% and 94%. About 37% of the studies generalised the report as blaCTX-M-positive E. coli. The use of sequencing in characterising the CTX-M-producing E. coli was reported in only 32% of all the studies. This review provides information on the epidemiology of CTX-M-15-producing E. coli in paediatric diarrhoea and the extent to which surveillance is being performed. This is relevant in informing clinical practice for the management of diarrhoea as well as the design of future surveillance studies.

7.
Diagn Microbiol Infect Dis ; 109(2): 116279, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38547800

RESUMO

BACKGROUND: Globally, millions of children die as a result of diarrhoea and/or antimicrobial resistant infections. Diarrhoeagenic Escherichia coli (DEC) are responsible for a substantial proportion of cases of diarrhoea in South Africa and sub-Saharan Africa. Effective treatments (including the use of antimicrobials) are therefore essential. METHODOLOGY: E. coli isolated from children under the age of five were subjected to antimicrobial susceptibility testing using the Vitek 2® compact automated system (bioMérieux Inc., France) and categorized as multidrug or extensively drug resistant (MDR or XDR). RESULTS: Almost all isolates (164/166, 98.8 %) were categorized as MDR with 4.9 % (9/166) categorized as XDR. The majority of isolates (153/166, 92.2 %) were also phenotypically classified as extended-spectrum ß-lactamase (ESBL) producers. More than half of these isolates (78/153, 51.0 %) were subjected to PCR for genes associated with ESBL production. More than half (45/78, 57.7 %) of the isolates tested were PCR positive for at least one ESBL gene or gene group and 11.5 % (9/78) were positive for two ESBL genes or gene groups. DISCUSSION: There is a need to strengthen antimicrobial resistance surveillance in South Africa and improve infection prevention and control measures. There is also a need to review the current South African Treatment Guidelines as outlined by the South African Essential Drugs Programme.


Assuntos
Antibacterianos , Diarreia , Farmacorresistência Bacteriana Múltipla , Infecções por Escherichia coli , Escherichia coli , Testes de Sensibilidade Microbiana , beta-Lactamases , Humanos , África do Sul/epidemiologia , Diarreia/microbiologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/epidemiologia , Lactente , Pré-Escolar , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Farmacorresistência Bacteriana Múltipla/genética , Antibacterianos/farmacologia , beta-Lactamases/genética , Masculino , Feminino , Recém-Nascido
8.
Antibiotics (Basel) ; 12(5)2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-37237708

RESUMO

Antimicrobial resistance (AMR) is a growing global public health threat. Furthermore, wastewater is increasingly recognized as a significant environmental reservoir for AMR. Wastewater is a complex mixture of organic and inorganic compounds, including antibiotics and other antimicrobial agents, discharged from hospitals, pharmaceutical industries, and households. Therefore, wastewater treatment plants (WWTPs) are critical components of urban infrastructure that play a vital role in protecting public health and the environment. However, they can also be a source of AMR. WWTPs serve as a point of convergence for antibiotics and resistant bacteria from various sources, creating an environment that favours the selection and spread of AMR. The effluent from WWTPs can also contaminate surface freshwater and groundwater resources, which can subsequently spread resistant bacteria to the wider environment. In Africa, the prevalence of AMR in wastewater is of particular concern due to the inadequate sanitation and wastewater treatment facilities, coupled with the overuse and misuse of antibiotics in healthcare and agriculture. Therefore, the present review evaluated studies that reported on wastewater in Africa between 2012 and 2022 to identify knowledge gaps and propose future perspectives, informing the use of wastewater-based epidemiology as a proxy for determining the resistome circulating within the continent. The study found that although wastewater resistome studies have increased over time in Africa, this is not the case in every country, with most studies conducted in South Africa. Furthermore, the study identified, among others, methodology and reporting gaps, driven by a lack of skills. Finally, the review suggests solutions including standardisation of protocols in wastewater resistome works and an urgent need to build genomic skills within the continent to handle the big data generated from these studies.

9.
Viruses ; 15(8)2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37632024

RESUMO

Acute gastroenteritis (AGE) accounts for considerable morbidity and mortality in the paediatric population worldwide, especially in low-income countries. Human norovirus (HNoV), particularly GII.4 strains, are important agents of AGE. This study aimed to detect and characterise HNoV in children with and without AGE. Between 2019 and 2021, 300 stool samples (200 AGE and 100 without AGE) were collected from children below 5 years of age referred to the healthcare facilities of the rural communities of Vhembe District, South Africa. After detection using real-time RT-PCR, HNoV positive samples were subjected to RT-PCR and Sanger sequencing. Partial nucleotide sequences (capsid/RdRp) were aligned using the Muscle tool, and phylogenetic analysis was performed using MEGA 11. The nucleotides' percent identity among HNoV strains was compared using ClustalW software. A significant difference in HNoV prevalence between AGE children (37%; 74/200) and non-AGE (14%; 14/100) was confirmed (p < 0.0001). Genogroup II (GII) HNoV was predominant in AGE children (80%; 59/74), whereas most non-AGE children were infected by the GI norovirus genogroup (64%; 9/14). GII.4 Sydney 2012 [P31] strains were dominant (59%; 19/32) during the study period. A phylogenetic analysis revealed a close relationship between the HNoV strains identified in this study and those circulating worldwide; however, ClustalW showed less than 50% nucleotide similarity between strains from this study and those from previously reported norovirus studies in the same region. Our findings indicate significant changes over time in the circulation of HNoV strains, as well as the association between high HNoV prevalence and AGE symptoms within the study area. The monitoring of HuNoV epidemiology, along with stringent preventive measures to mitigate the viral spread and the burden of AGE, are warranted.


Assuntos
Norovirus , Humanos , Criança , Pré-Escolar , Prevalência , Norovirus/genética , População Rural , África do Sul/epidemiologia , Filogenia , Nucleotídeos
10.
Antibiotics (Basel) ; 12(8)2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37627765

RESUMO

Diarrheagenic Escherichia coli (DEC) pathotypes are the leading cause of mortality and morbidity in South Asia and sub-Saharan Africa. Daily interaction between people contributes to the spreading of Escherichia coli (E. coli), and fomites are a common source of community-acquired bacterial infections. The spread of bacterial infectious diseases from inanimate objects to the surrounding environment and humans is a serious problem for public health, safety, and development. This study aimed to determine the prevalence and antibiotic resistance of diarrheagenic E. coli found in toilets and kitchen cloths in the Vhembe district, South Africa. One hundred and five samples were cultured to isolate E. coli: thirty-five samples were kitchen cloths and seventy-five samples were toilet swabs. Biochemical tests, API20E, and the VITEK®-2 automated system were used to identify E. coli. Pathotypes of E. coli were characterised using Multiplex Polymerase Chain Reaction (mPCR). Nine amplified gene fragments were sequenced using partial sequencing. A total of eight antibiotics were used for the antibiotic susceptibility testing of E. coli isolates using the Kirby-Bauer disc diffusion method. Among the collected samples, 47% were positive for E. coli. DEC prevalence was high (81%), with ETEC (51%) harboring lt and st genes being the most dominant pathotype found on both kitchen cloths and toilet surfaces. Diarrheagenic E. coli pathotypes were more prevalent in the kitchen cloths (79.6%) compared with the toilet surfaces. Notably, hybrid pathotypes were detected in 44.2% of the isolates, showcasing the co-existence of multiple pathotypes within a single E. coli strain. The antibiotic resistance testing of E. coli isolates from kitchen cloths and toilets showed high resistance to ampicillin (100%) and amoxicillin (100%). Only E. coli isolates with hybrid pathotypes were found to be resistant to more than three antibiotics. This study emphasizes the significance of fomites as potential sources of bacterial contamination in rural settings. The results highlight the importance of implementing proactive measures to improve hygiene practices and antibiotic stewardship in these communities. These measures are essential for reducing the impact of DEC infections and antibiotic resistance, ultimately safeguarding public health.

11.
Pathogens ; 12(2)2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36839587

RESUMO

Infectious diarrhoea contributes to high morbidity and mortality in young children from sub-Saharan Africa. The aim of this study was to assess the prevalence of single and multiple diarrhoeal-causing pathogen combinations in children suffering from diarrhoea from rural and peri-urban communities in South Africa. A total of 275 diarrhoea stool specimens were collected between 2014 and 2016 from Hospitals and Primary Health Care clinics. The BioFire® FilmArray® Gastrointestinal panel was used to simultaneously detect 22 diarrhoea pathogens (viruses, bacteria, parasites) known to cause diarrhoea. A total of 82% (226/275) enteric pathogens were detected in the stool specimens. The two most detected bacterial, viral and parasitic pathogens each included: EAEC (42%), EPEC (32%), Adenovirus F40/41 (19%), Norovirus (15%), Giardia (8%) and Cryptosporidium (6%), respectively. Single enteric pathogen infections were recorded in 24% (65/275) specimens with EAEC, and Norovirus was found in 26% (17/65) and 14% (9/65) of the specimens, respectively. Multiple enteric pathogen combinations were recorded in 59% (161/275) of the stool specimens with 53% (85/161) containing two pathogens, 22% (35/161) containing three pathogens and 25% (41/161) containing four or more pathogens. The results from this study demonstrated the complex nature of pathogen co-infections in diarrhoeal episodes which could have an impact on treatment effectiveness.

12.
Pathogens ; 12(8)2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37623975

RESUMO

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M. tb), remains a significant global health issue, with high morbidity and mortality rates. The emergence of drug-resistant strains, particularly multidrug-resistant TB (MDR-TB), poses difficult challenges to TB control efforts. This comprehensive review and meta-analysis investigated the prevalence of and molecular insights into isoniazid (INH) and rifampicin (RIF) resistance-conferring mutations in M. tb isolates from South Africa. Through systematic search and analysis of 11 relevant studies, we determined the prevalence of gene mutations associated with RIF and INH resistance, such as rpoB, katG, and inhA. The findings demonstrated a high prevalence of specific mutations, including S450L in rpoB, and S315T, which are linked to resistance against RIF and INH, respectively. These results contribute to the understanding of drug resistance mechanisms and provide valuable insights for the development of targeted interventions against drug-resistant TB.

13.
Viruses ; 15(11)2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-38005863

RESUMO

Norovirus (NoV) is the leading cause of viral gastroenteritis, mostly affecting young children worldwide. However, limited data are available to determine the severity of norovirus-associated AGE (acute gastroenteritis) and to correlate it with the NoV-specific IgA antibodies' level. Between October 2019 and September 2021, two hundred stool samples were randomly collected from symptomatic cases for the vesikari score and NoV-specific IgA assessment in young children from rural South Africa. Additionally, one hundred saliva specimens were concomitantly sampled within the same cohort to evaluate the NoV-specific salivary IgA levels. In addition, 50 paired saliva and stool samples were simultaneously collected from asymptomatic children to serve as controls. NoV strains in stool samples were detected using real-time RT-PCR, amplified, and genotyped with RT-PCR and Sanger sequencing. ELISA using NoV VLP (virus-like particles) GII.4 as antigens was performed on the saliva specimens. Dehydrated children were predominantly those with NoV infections (65/74, 88%; p < 0.0001). NoV-positive infections were significantly associated with the severe diarrhea cases having a high vesikari score (55%, 33/60) when compared to the non-severe diarrheal score (29.3%, 41/140; p < 0.0308). NoV of the GII genogroup was mainly detected in severe diarrhea cases (50.9%, 30/59; p = 0.0036). The geometric means of the NoV-specific IgA level were higher in the asymptomatic NoV-infected group (0.286) as compared to the symptomatic group (0.174). This finding suggests that mucosal immunity may not protect the children from the NoV infection. However, the findings indicated the contribution of the pre-existing NoV-specific IgA immune response in reducing the severity of diarrheal disease. A high vesikari score of AGE associated with the NoV GII genogroup circulating in the study area underscores the need for an appropriate treatment of AGE based on the severity level of NoV-associated clinical symptoms in young children.


Assuntos
Infecções por Caliciviridae , Gastroenterite , Norovirus , Humanos , Criança , Lactente , Pré-Escolar , África do Sul/epidemiologia , Fezes , Gastroenterite/epidemiologia , Gastroenterite/diagnóstico , Diarreia , Genótipo , Norovirus/genética , Infecções por Caliciviridae/diagnóstico , Infecções por Caliciviridae/epidemiologia , Imunoglobulina A , Filogenia
14.
Adv Virol ; 2022: 9928378, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35693126

RESUMO

Background: Viral diarrhoea is a concern in acute gastroenteritis cases among children younger than 5 years of age. Sapovirus has been noted as an emerging causative agent of acute gastroenteritis worldwide. Objective/Study Design. The aim of this study was to characterize human sapoviruses targeting the VP1 (NVR and N-terminal) region. Twenty-five samples were randomly selected from 40 sapovirus-positive samples previously detected and analyzed for the VP1 region using the One-Step RT-PCR assay. The PCR products were subjected to Sanger sequencing analysis. Results: The polyprotein segment (NVR and N-terminal) was successfully amplified from 10/25 samples. Sapovirus GI.1 was the most predominant strain (6/10; 60%), followed by SV-GII.1 (2/10; 20%) and 10% of each GI.3 and GII.3. Conclusion: Through the partial analysis of the VP1 region, this study provides more data to add on the human sapovirus genetic characterization of circulating strains in South Africa, with the proposition of further analysis of sapovirus VP1 fragments for the viral structure and function.

15.
Int J Infect Dis ; 114: 226-232, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34775113

RESUMO

BACKGROUND: Diarrhoeagenic Escherichia coli pose a significant risk to human health. As such, determining the source(s) of these bacteria when isolated from patients with diarrhoea is an important step in disease prevention. OBJECTIVES: To identify the presence of genes coding for virulence and phylogroups among E. coli isolated from children hospitalized due to diarrhoea in Limpopo Province, South Africa. METHODS: E. coli isolates were identified using the VITEK-2 automated system. An 11-gene multiplex polymerase chain reaction (PCR) was used to differentiate five pathogenic types of E. coli: enteroaggregative (EAEC), enteroinvasive (EIEC), enterohaemorrhagic (EHEC), enteropathogenic (EPEC) and enterotoxigenic (ETEC). The Clermont quadruplex PCR method was used to identify phylogroups of isolates. RESULTS: From the 133 isolates tested, 79 were confirmed as E. coli. Of these, 19.0% (15/79) were commensals and 81.0% (64/79) were positive for at least one pathotype, of which ETEC was predominant (16.5%, 13/79), followed by EAEC (10.1%, 8/79), EPEC (7.6%, 6/79) and EHEC (2.5%, 2/79). Hybrid pathotypes were also detected and EAEC/ETEC was predominant (25.3%, 20/79). Phylogroup B2 was predominant (30.4%, 24/79), followed by phylogroup B1 (22.8%, 18/79), and phylogroups C and E (both 12.7%, 10/79). Just over 6% (5/79) of isolates were non-typable. CONCLUSION: There was a high distribution of diarrhoeagenic E. coli associated with different phylogroups among children living in Limpopo Province, South Africa. This emphasizes the importance of future monitoring of virulence and phylogroup distribution of E. coli isolates in this province in particular and in South Africa as a whole.


Assuntos
Infecções por Escherichia coli , Escherichia coli , Criança , Diarreia , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Humanos , Reação em Cadeia da Polimerase Multiplex , Filogenia , Prevalência , África do Sul/epidemiologia , Virulência/genética
16.
Braz J Microbiol ; 53(4): 1781-1787, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35882715

RESUMO

Bundle-forming pili (BFP) are implicated in the virulence of typical enteropathogenic E. coli (EPEC), resulting in enhanced colonization and mild to severe disease outcomes; hence, non-functional BFP may have a major influence on disease outcomes in vivo. Weaned antibiotic pre-treated C57BL/6 mice were orally infected with EPEC strain UMD901 (E2348/69 bfpA C129S); mice were monitored daily for body weight; stool specimens were collected daily; and intestinal tissues were collected at the termination of the experiment on day 3 post-infection. Real-time PCR was used to quantify fecal shedding and tissue burden. Intestinal inflammatory biomarkers lipocalin-2 (LCN-2) and myeloperoxidase (MPO) were also assessed. Infection caused substantial body weight loss, bloody diarrhea, and intestinal colonization with fecal and intestinal tissue inflammatory biomarkers that were comparable to those previously published with the wild-type typical EPEC strain. Here we further report on the evaluation of an EPEC infection model, showing how disruption of bfp function does not impair, and may even worsen diarrhea, colonization, and intestinal disruption and inflammation. More research is needed to understand the role of bfp in pathogenicity of EPEC infections in vivo.


Assuntos
Escherichia coli Enteropatogênica , Infecções por Escherichia coli , Proteínas de Escherichia coli , Animais , Camundongos , Aderência Bacteriana , Diarreia , Escherichia coli Enteropatogênica/genética , Infecções por Escherichia coli/microbiologia , Inflamação , Camundongos Endogâmicos C57BL
17.
Pathogens ; 11(6)2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35745490

RESUMO

BACKGROUND: In 2018, an estimated 10.0 million people contracted tuberculosis (TB), and 1.5 million died from it, including 1.25 million HIV-negative persons and 251,000 HIV-associated TB fatalities. Drug-resistant tuberculosis (DR-TB) is an important contributor to global TB mortality. Multi-drug-resistant TB (MDR-TB) is defined as TB resistant to at least isoniazid (INH) and rifampin (RMP), which are recommended by the WHO as essential drugs for treatment. OBJECTIVE: To investigate the effectiveness of bedaquiline addition to the treatment of drug-resistant TB infections on the African continent. METHODOLOGY: The search engine databases Medline, PubMed, Google Scholar, and Embase were used to obtain published data pertaining to DR-TB between 2012 and 2021 in Africa. Included studies had to document clinical characteristics at treatment initiation and outcomes at the end of treatment (i.e., success, failure, recurrence, loss to follow-up, and death). The included studies were used to conduct a meta-analysis. All data analysis and visualization were performed using the R programming environment. The log risk ratios and sample variances were calculated for DR-TB patients treated with BBQ monotherapy vs. BDQ and other drug therapy. To quantify heterogeneity among the included studies, random effect sizes were calculated. RESULTS: A total of 16 studies in Africa from Mozambique (N = 1 study), Eswatini (N = 1 study), Democratic Republic of the Congo (N = 1 study), South Africa (N = 12 studies), and a multicenter study undertaken across Africa (N = 1 study) were included. In total, 22,368 individuals participated in the research studies. Among the patients, (55.2%; 12,350/22,368) were male while 9723/22,368 (44%) were female. Overall, (9%; 2033/22,368) of patients received BDQ monotherapy, while (88%; 19,630/22,368) patients received bedaquiline combined with other antibiotics. In total, (42%; 9465/22,368) of the patients were successfully treated. About (39%; 8653/22,368) of participants finished their therapy, meanwhile (5%; 1166/22,368) did not finish their therapy, while people (0.4%; 99/22,368) were lost to follow up. A total of (42%; 9265/22,368) patients died. CONCLUSION: Very few studies on bedaquiline usage in DR-TB in Africa have been published to date. Bedaquiline has been shown to enhance DR-TB results in clinical studies and programmatic settings. Hence, the World Health Organization (WHO) has recommended that it be included in DR-TB regimens. However, in the current study limited improvement to DR-TB treatment results were observed using BDQ on the continent. Better in-country monitoring and reporting, as well as multi-country collaborative cohort studies of DR-TB, can expand the knowledge of bedaquiline usage and clinical impact, as well as the risks and benefits throughout the continent.

18.
J Infect Dis ; 202 Suppl: S148-55, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20684695

RESUMO

BACKGROUND: Data regarding the prevalence and molecular epidemiology of rotavirus infection in rural areas of Africa are limited. In this study the prevalence and genetic diversity of rotaviruses in a rural South African setting were investigated. METHODS: During June 1998 to June 2000, 420 stool specimens were collected from children with acute diarrhea who visited primary health care clinics in the rural Vhembe region, Limpopo Province, South Africa. Group A rotaviruses were detected by enzyme-linked immunosorbent assay, and the G and P types were determined by reverse-transcription polymerase chain reaction. RESULTS: Of the 420 specimens, 111 (26.4%) were positive for group A rotavirus; P[6]G1 strains predominated (32.4%), followed by P[8]G1 (13.5%), P[6]G9 (4.5%), P[4]G8 (3.6%), P[4]G1 (3.6%), P[6]G8 (3.6%), and P[6]G2 (2.7%). Dual infections, with >1 P type, were seen in 33 (37.1%) of the positive specimens. CONCLUSION: The unusual serotype and genotype combinations of rotavirus circulating in the rural communities of the Limpopo Province highlight the need for more studies to monitor the geographic distribution of rotavirus strains in rural African settings.


Assuntos
Diarreia/epidemiologia , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/genética , Antígenos Virais/genética , Proteínas do Capsídeo/genética , Pré-Escolar , Variação Genética , Genótipo , Humanos , Lactente , Recém-Nascido , Epidemiologia Molecular , Prevalência , População Rural , África do Sul/epidemiologia
19.
J Infect Dis ; 202 Suppl: S55-63, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20684719

RESUMO

Serotype G9 strains have been detected sporadically and in localized outbreaks in various African countries, including South Africa, Botswana, Malawi, Kenya, Cameroon, Nigeria, Ghana, Guinea-Bissau, Libya, and Mauritius. Serotype G9 strains were analyzed to investigate genogroup characteristics, including subgroup specificity, electropherotype, and P and G genotypes. In addition, the antigenic composition of the South African G9 strains was assessed. African G9 strains were associated with both DS-1-like characteristics and Wa-like characteristics, indicating the predisposition of G9 strains to frequently reassort. Despite these reassortment events, serotype G9 strains appear to maintain antigenic character in the outer capsid protein, as evident with the reaction of the South African G9 strains with the G9-specific monoclonal antibody F45:1. Phylogenetic analysis clustered African G9 strains geographically, regardless of genogroup characteristics, into 1 lineage (IIId). Two groups of G9 strains, originating in India and Japan, were identified in this lineage. Continuous surveillance of circulating rotavirus strains in Africa is vital to prepare for future vaccine implementation on a continent that clearly needs such preventative medicines.


Assuntos
Infecções por Rotavirus/virologia , Rotavirus/classificação , África/epidemiologia , Sequência de Aminoácidos , Clonagem Molecular , Fezes/virologia , Regulação Viral da Expressão Gênica/fisiologia , Genótipo , Humanos , Dados de Sequência Molecular , Filogenia , Rotavirus/genética , Infecções por Rotavirus/epidemiologia , Sorotipagem , Proteínas Virais/genética , Proteínas Virais/metabolismo
20.
Viruses ; 13(3)2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33804579

RESUMO

Diarrhoeal disease is considered an important cause of morbidity and mortality in developing areas, and a large contributor to the burden of disease in children younger than five years of age. This study investigated the prevalence and genogroups of human sapovirus (SV) in children ≤5 years of age in rural communities of Vhembe district, South Africa. Between 2017 and 2020, a total of 284 stool samples were collected from children suffering with diarrhoea (n = 228) and from children without diarrhoea (n = 56). RNA extraction using Boom extraction method, and screening for SV using real-time PCR were done in the lab. Positive samples were subjected to conventional RT-PCR targeting the capsid fragment. Positive sample isolates were genotyped using Sanger sequencing. Overall SV were detected in 14.1% (40/284) of the stool samples (16.7% (38/228) of diarrhoeal and 3.6% (2/56) of non-diarrhoeal samples). Significant correlation between SV positive cases and water sources was noted. Genogroup-I was identified as the most prevalent strain comprising 81.3% (13/16), followed by SV-GII 12.5% (2/16) and SV-GIV 6.2% (1/16). This study provides valuable data on prevalence of SV amongst outpatients in rural and underdeveloped communities, and highlights the necessity for further monitoring of SV circulating strains as potential emerging strains.


Assuntos
Infecções por Caliciviridae , Diarreia , Sapovirus , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Pré-Escolar , Estudos Transversais , Diarreia/epidemiologia , Diarreia/virologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , População Rural , Sapovirus/genética , Sapovirus/isolamento & purificação , África do Sul/epidemiologia
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