Limitation in detecting African cassava mosaic geminivirus in the lignified tissues of cassava stems

Field-infected cassava stems whose leaves were identified with differential symptoms of African cassava mosaic geminivirus (ACMV) disease were assessed for index of severity of symptoms (ISS) todetermine their infection status by scoring young resultant plants in the laboratory. Extracts of young stem tissues and leaves of emergent shoots from topped stems were also assayed for occurrence ofACMV by the enzyme-linked immunosorbent assay (ELISA). Geminivirus disease incidence and severity of symptoms were most abundant on leaves of plants from cuttings of field-symptomatic (I) stems of the moderately-resistant TMS 4(2)1425 (63.2%) and the susceptible TMS 60506 (51.1%) genotypes while those from apparently symptom-free (H) stems of the resistant genotype TMS 30001 recorded significantly the least disease (0%). Similarly, the index of severity of symptoms on all plants (ISSAP) and diseased plants only (ISSDP) were significantly highest on leaves of TMS 4(2)1425 (2.42 and 2.83), and were significantly the least (1) on leaves of TMS 30001, respectively. ACMV was not detected inextracts of all sections of lignified cassava stems by ELISA as all absorbance values were below threshold (0.0890). However, the virus was detected at greater concentrations in leaves of emergentaxillary shoots regenerating on topped plants of all node types of TMS 60506 and TMS 4(2)1425 as well as the base (node 1) of TMS 30001 stems but not on those from middle and uppermost nodes (10 and20, respectively) of the latter genotype. The highest absorbance values were recorded on shoots on node 1 of TMS 60506 (0.1720 ± 0.096), TMS 4(2)1425 (0.1640 ± 0.115) and TMS 30001 (0.1580 ± 0.080) inthat order, while the least values were on nodes 10 (0.0298 ± 0.020) and 20 (0.0289 ± 0.019) of TMS 30001

Increasing trend of metronidazole resistance in the treatment of Helicobacter pylori infection: A global challenge

Helicobacter pylori are gram negative spiral bacteria that colonize the human stomach. Infection with H. pylori is associated with chronic gastritis, peptic ulcer, gastric adenocarcinoma and gastric mucosaassociatedlymphoid tissue (MALT) lymphoma. Antibiotic resistance is an ever increasing problem with the treatment of most microbial infections including H. pylori; and has become a growing problem worldwide with the eradication of this organism. In recent years, several treatment regimens have been proposed for H. pylori eradication. However, the only conditions for which such treatment is strongly recommended on the basis of unequivocal supporting evidence are peptic ulcer disease and low gradegastric MALT lymphoma. Success of antimicrobial regimens for H. pylori eradication depends on patient compliance and lack of antimicrobial resistance. Metronidazole (Mtz) containing regimens have been shown to limit effectiveness because of increasing prevalence of resistance to this drug. A high prevalence (> 90%) of Mtz resistance in H. pylori has been reported especially in developing countries. Mtz resistance may be mediated through an inability of Mtz-resistant strains to remove oxygen from the site of Mtz reduction, thereby preventing Mtz activation. This has been attributed to a mutation on the frxA and/or rdxA genes resulting in strains of the organism with defective nitro-reductases coded bythese genes. Infection by Mtz or amoxicillin resistant strains is an important factor leading to treatment failure; subjecting all H. pylori clinical isolates to susceptibility testing most especially to Mtz is recommended. If not possible, a program to survey the prevalence of resistance should beimplemented in a given area or population. This increasing emergence of antimicrobial resistance in H.pylori treatment posses serious public health problems and is therefore necessary that new drug regimens be examined

Cytotoxicity Of Three South African Medicinal Plants Using The Chang Liver Cell Line

Background: Arctotis arctotoides, Gasteria bicolor and Pittosporum viridiflorum are commonly used in the Eastern Cape, South Africa by traditional healers for the treatment of opportunistic fungal infections in HIV/AIDS patients. Unfortunately, there is a dearth of published data regarding the toxicity of the selected plants, despite the fact that experimental screening of toxicity is crucial to guarantee the safety of the users.Materials and Methods: Therefore, it was decided to evaluate the cytotoxicity of the hexane and acetone extracts of the medicinal plants against the Chang Liver cell line using the in vitro MTT assay. Different concentrations of the extracts were added into 24-hour cultured cells and incubated for 72 hours under specific condition (37 °C, 5% CO2). Cell survival was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2,  5-diphenyltetrazolium bromide (MTT) assay.Results: Depending on the dosage and duration of treatment, the cytotoxic effects of Gasteria bicolor and Pittosporum viridiflorum were considered relatively weak (but not entirely absent) and less of a toxicity risk. Arctotis arctotoides extracts were the most toxic both in terms of IC50 values as well as the steeper slope of the dose response curve. The IC50 values for the acetone and hexane extracts of this plant were 17.4 and 12.4 μg/ml respectively.Conclusion: These relatively low values raise concern for potential hepatotoxic effects and deserve further investigation or at least a warning to potential users.Keywords: Cytotoxicity; medicinal plants; opportunistic fungal infections; Chang liver cell lin

Polyphenolic content and in vitro antioxidant evaluation of the stem bark extract of Peltophorum africanum sond (Fabaceae)

Background: Peltophorum africanum has been traditionally used to relief stress induced diseases. The study was aimed to evaluate the antioxidant activities of ethyl acetate extract.Material and methods: The in vitro antioxidant activities of Peltophorum africanum stem bark extract was examined in this study by means of +radical scavenging and ferric reducing power analysis using 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2`-azino-bis (3-ethylbenzthiazoline-6- sulfonic acid (ABTS) kit, hydrogen peroxide (H2O2), iron (iii) chloride (Fe3+) and nitric oxide (NO). In assessing the likely effects of secondary metabolites on the activities observed; total proanthocyanidins, phenolics, flavonols, and flavonoids were determined using standard phytochemical methods. Data was analyzed by ANOVA test and the p-value < 0.05 was considered significant.Results: Extract scavenging activity of 88.73± 6.69 % (25 μg mL-1), 53.93±1.09 % (25 μg mL-1), 87.293±6.64 % (25 μg mL-1), 10.55±2.16 mM (0.42 mM) and 3.8115±0.06 (25 μg mL-1) were recorded for H2O2, NO, DPPH, ABTS and Fe3+ reducing power respectively. These values were comparable to the standard compounds; DBPC*BHT, L (+) - Ascorbic acid and Trolox™ (p < 0.05). Proanthocyanidins (92.18±4.68 mg/g) occurred more (p < 0.05) in the extract when compared to all other compounds tested: phenolics (60.53±1.46 mg/g) > flavonoids (18.37± 2.11 mg/g), > flavonols (11.20±3.90 mg/g). However the difference between flavonols and flavonoids was not significant (p > 0.05) at 95% confidence interval.Conclusion: The results of this study validated the folkloric use of P. africanum which could be exploited as an easily available and a cheaper source of natural antioxidants.Key words: Peltophorum africanum, antioxidant, phytochemicals, polyphenolics, radicals

Helicobacter pylori prevalence in dyspeptic patients in the Eastern Cape province – race and disease status

Objectives. We examined Helicobacter pylori infection in patients with gastric-related morbidities at Livingstone Hospital, Port Elizabeth, to determine the prevalence and risk factors for infection according to race, endoscopic diagnosis, age and sex. Methods. Gastric biopsies were collected from 254 consecutive patients and H. pylori was isolated on Columbia agar base supplemented with 7% sheep’s blood and Skirrow’s supplement containing trimethoprim (2.5 mg), vancomycin (5 mg) and cefsulodin (2.5 mg). Amphotericin (2.5 mg) was added to the medium. Recovered isolates were identified following standard microbiology and biochemical techniques. Presumptive isolates were further confirmed by polymerase chain reaction (PCR) targeting the glmM gene. Fisher’s exact test was used to assess the univariate association between H. pylori infection and the possible risk factors. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to measure the strength of association, using EPI INFO 3.41 software. p-value

Treatment of Helicobacter pylori infections: Mitigating factors and prospective natural remedies

Helicobacter pylori is a Gram-negative, microaerophilic spiral or motile rod that infects about half the world’s population with a very high prevalence in the developing world. It is an important aetiological factor in the development of gastritis, peptic ulcer disease, gastric atrophy and B cell mucosa associated lymphoid tissue (MALT) lymphoma. H. pylori infection is responsible for a significant cause of morbidity and mortality imposing a major burden on health care systems world wide. The high prevalence of infection in the developing countries has been attributed to poor socioeconomic status and sanitation as well as an increased trend of antibiotic resistance. Antimicrobial chemotherapy (two antibiotics and a proton pump inhibitor) employed for the treatment of H. pylori infections has emerged as the most important means to resolve these infections. However, antimicrobial therapy is fraught with a number of inherent limitations such as resistance, cost of treatment, unavailability of drugs in rural areas and undesirable side effects necessitating the need to search for alternative approaches from natural sources including vegetables, honey and probiotics amongst others. These could form the basis of novel low cost, efficient, large-scale and alternative/complementary solutions with minimal side effects to decrease or eradicate H. pylori infections in the future

49 Marked susceptibility of South African Helicobacter pylori strains to ciprofloxacin and amoxicillin: Clinical implications

Objectives. Helicobacter pylori-associated infection is commonin South Africa, as in other developing countries. Antibioticresistance is recognised as a major cause of treatment failure.We studied the susceptibility and resistance patterns of H.pylori to guide empiric treatment and prevent the emergenceof resistance.Methods. Two hundred H. pylori strains obtained from gastricbiopsies of patients presenting with gastric-related morbiditiesattending Livingstone Hospital, Port Elizabeth, were evaluatedfor their susceptibility to seven antibiotics – metronidazole,clarithromycin, tetracycline, amoxicillin, gentamicin, ciprofloxacin and erythromycin. H. pylori was isolated following standard microbiology procedures, and susceptibility determined using the Kirby-Bauer disc diffusion and agar dilution methods. Comparisons of antimicrobial resistance rates with sex of the patients were determined using the chisquare test; a p-value o

In vitro anti-Helicobacter pylori activity of Lycopodium cernuum (Linn) Pic. Serm

Helicobacter pylori, a gram negative microaerophilic bacterium is a major etiological agent in duodenal, peptic and gastric ulcers. In this study, gastric biopsy samples were obtained from patients presentingwith gastroduodenal complications. H. pylori was isolated from the specimens following standard microbiology procedures, and isolates subjected to pure fractions of Lycopodium cernuum extracts forantimicrobial assays. Extracts were fractionated by partition chromatography with solvents of increasing polarity to obtain pure fractions. The disk diffusion method was used to determine thesusceptibility of 15 strains of H. pylori to the fractions. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the most active fraction was also determined by thebroth dilution method. Results were analyzed by the Fisher’s exact test. All the fractions tested demonstrated antimicrobial activity with zone diameters of inhibition between 0 - 30 mm. Of the 5 fractions obtained, the hexane (Hex) fraction was the most active. The lowest MIC and MBC recorded for the hexane (Hex) fraction were 0.016 and 0.125 mg/mL, respectively. There was no statistically significant difference (P>0.05) in the potency of the fraction on the different bacterial strains tested, both for the MIC and MBC. It is concluded that this plant may contain compounds with therapeutic activity, which may be found in the Hex fraction (100%)

Aquatic Hemiptera in Southwest Cameroon: Biodiversity of Potential Reservoirs of Mycobacterium ulcerans and multiple wolbachia sequence types revealed by metagenomics

Buruli ulcer (BU), caused by Mycobacterium ulcerans, is a neglected tropical disease associated with freshwater habitats. A variety of limnic organisms harbor this pathogen, including aquatic bugs (Hemiptera: Heteroptera), which have been hypothesized to be epidemiologically important reservoirs. Aquatic Hemiptera exhibit high levels of diversity in the tropics, but species identification remains challenging. In this study, we collected aquatic bugs from emerging foci of BU in the Southwest Region of Cameroon, which were identified using morphological and molecular methods. The bugs were screened for mycobacterial DNA and a selection of 20 mycobacteria-positive specimens from the families Gerridae and Veliidae were subjected to next-generation sequencing. Only one individual revealed putative M. ulcerans DNA, but all specimens contained sequences from the widespread alphaproteobacterial symbiont, Wolbachia. Phylogenetic analysis placed the Wolbachia sequences into supergroups A, B, and F. Circularized mitogenomes were obtained for seven gerrids and two veliids, the first from these families for the African continent. This study suggests that aquatic Hemiptera may have a minor role (if any) in the spread of BU in Southwest Cameroon. Our metagenomic analysis provides new insights into the incursion of Wolbachia into aquatic environments and generated valuable resources to aid molecular taxonomic studies of aquatic Hemiptera. © 2019 by the authors

Helicobacter pylori infection and transmission in Africa: Household hygiene and water sources are plausible factors exacerbating spread

Helicobacter pylori (H. pylori) is a microaerophilic motile curve rod that inhabits the gastric mucosa of the human stomach. The organism chronically infects billions of people worldwide and is one of themost genetically diverse of bacterial species. Infection with the bacterium which leads to chronic gastritis, peptic ulceration, gastric cancers and gastric malt lymphoma has been reported to follow a pattern linked to geographic and socio-demographic factors. Studies have documented a higherprevalence in Africa than elsewhere although the pathological outcomes do not correlate with infection. H. pylori transmission pathways are still vague, but the risks of transmission include precarious hygiene standards, over-crowding and contaminated environment and water sources amongst others. The possible routes of transmission include oral-oral, faecal-oral and person- to -person, either with or without transitional transmission steps during episodes of diarrhoea or gastro-oral contact in the eventof vomiting. Use of contaminated water including municipal tap water has also been suspected to have a high impact in the transmission of the organism. To generate the data presented in this paper, we conducted an internet based search on relevant literature pertaining to H. pylori epidemiology in general and Africa in particular. Sites such as Pubmed, AJOL, Scopus and Goggle scholar were mainly used. This paper therefore attempts to appraise the role of household hygiene and water sources in the transmission of this organism in the developing world context