Fungal foodborne diseases pose serious public health problems and cause significant loss of the world's food stock as a result of toxic contamination. Hence the need to find solutions to foodborne fungal contaminants. This study investigated the antifungal and phytochemical properties of Moringa oleifera leaves and seeds using various extraction solvents (acetone, water, ethanol and methanol). Aspergillus flavus and Aspergillus niger isolated from food samples were used as test organisms. The Agar Well Diffusion method was used to determine the antifungal activities of Moringa oleifera leave and seed extracts, while standard phytochemical tests were used to analyze for the phytochemicals. Moringa oleifera leave and seed extracts showed the presence of glycosides, flavonoids, alkaloids, tannins, saponins, phenols and hydrolysable tannins after the chemical test. At 100 mg/ml for Methanol extract, the leaves gave wider zones of inhibition (18.33 mm against A. flavus and 17.17 mm against A. niger) than the seed extract (16.50 mm against A. flavus and 16.33 mm against A. niger) for all test organism. The activity of the extracts were however lower than Sodium benzoate (33 mm at 100 mg/ml), as standard. The Minimum Inhibition Concentration of the plant extracts was most active at 25 mg/ml. Moringa oleifera leaves and seeds extracts may serve as natural antifungals for controlling growth of food spoilage fungi, and therefore may be used as a bio-preservative agent for prolonging the shelf-life of food products.
The transmission of Buruli ulcer (BU), caused by Mycobacterium ulcerans (MU), remains puzzling although a number of hypothesis including through bites of infected aquatic insects have been proposed. We report the results of experiments using ICR mice that give credence to our hypothesis that Acanthamoeba species may play a role in BU transmission. We cocultured MU N2 and MU 1615 which expresses red fluorescent protein (RFP) and Acanthamoeba polyphaga (AP), and confirmed infected AP by Ziehl-Neelsen (ZN) staining. We tested for viability of MU inside AP and observed strong RFP signals inside both trophozoites and cysts after 3 and 42 days of coculturing respectively. ICR mice were topically treated, either on shaved intact or shaved pinpricked rumps, with one of the following; MU N2 only (2.25 x 106 colony forming units [CFU] / ml), MU N2:AP coculture (2.96 x 104 CFU: 1.6 x 106 cells/ml), AP only (1.6 x 106 cells/ml), PYG medium and sterile distilled water. Both MU N2 only and MU N2:AP elicited reddening on day (D) 31; edema on D 45 and D 44 respectively, and ulcers on D 49 at pinpricked sites only. To ascertain infectivity and pathogenicity of MU N2 only and MU N2:AP, and compare their virulence, the standard mouse footpad inoculation method was used. MU N2:AP elicited reddening in footpads by D 3 compared to D 14 with MU N2 only of the same dose of MU N2 (2.96 x 104 CFU). ZN-stained MU were observed in both thin sectioned and homogenized lesions, and aspirates from infected sites. Viable MU N2 were recovered from cultures of the homogenates and aspirates. This study demonstrates in ICR mice MU transmission via passive infection, and shows that punctures in the skin are prerequisite for infection, and that coculturing of MU with AP enhances pathogenesis.
Replacement of organic solvents and short time for purification of polysaccharides has gained attention of researchers. Ionic liquid (IL) was optimally utilized to achieve the mentioned target. IL was coupled with ultrasound irradiation to obtain good yield of partially purified Moringa oleifera leaf polysaccharides. The yield of purified polysaccharides (75.11%) was close to the predicted (75.78%). Crude polysaccharides were found to be round group‐like shape while purified polysaccharides displayed compact flat thick‐slice shape under scanning electron microscopy. Using gas chromatography, galacturonic acid was detected as part of monosaccharide composition of crude polysaccharides. Functional groups associated with polysaccharides were confirmed using Fourier transform infrared spectroscopy. Using Congo red assay, polysaccharides were observed to be of nonhelical structure. The crude polysaccharide was more viscous in rheological property and had molecular weight of (304,700 g/mol). Using dynamic light scattering methodology, purified polysaccharides (24,370 g/mol) aggregated in water and possessed an excellent ABTS antiradical ability. Purification of polysaccharides using IL within a short time was feasible and presented useful characteristics needed in formulations by the food and pharmaceutical industries. Practical application Feasibility of using ionic liquid aqueous two‐phase system to separate biomolecules (amino acids, saccharides) within a short time has been established by researchers. Knowledge on this was applied in the separation of proteins from polysaccharides extracted from Moringa oleifera leaf. Knowledge of structure–function relations was thoroughly established for extracted and purified polysaccharides. Characteristics of polysaccharides discovered can be useful to the food and pharmaceutical industries.
Introduction: Klebsiella pneumoniae are among the most common cause of urinary tract infections such as cystitis and pyelonephritis. These multi-drug resistant K. pneumoniae are producers of extended spectrum beta-lactamases (ESBL) that are capable of hydrolyzing beta-lactams and non-beta-lactams. This laboratory-based study sought to establish the increase of ESBL-producing K. pneumoniae in multi-drug resistant urinary tract infections and determine the effective antibiotic treatment options. Methods: One hundred and seventy five K. pneumoniae isolates obtained from urine cultures were randomly collected and the combined disc synergy method was used to determine the ESBL-producing K. pneumoniae. The Vitek 2 system (bioMérieux, France) was used to perform antimicrobial susceptibility testing of 17 commonly used antibiotics. The data from the work was collated and statistically analysed using the chi-square test and Mann-Whitney U test. P values < 0.05 were considered significant. Results: Of the 175 K. pneumoniae responsible for urinary tract infections, 73.7% were producing ESBL suggesting that most urinary tract infections caused by K. pneumoniae will be multi-drug resistant. The antimicrobial resistance differences between ESBL-producing and non-ESBL-producing Klebsiella pneumoniae indicated a significance difference with p < 0.05. This study indicated that imipenem and amikacin are the antibiotic of choice for the treatment of multi-drug resistant urinary tract infections caused by ESBL-producing K. pneumoniae. Cephalosporins and nitrofurantoin are suitable for the treatment of urinary tract infections due to non-ESBL-producing K. pneumoniae. Conclusion: This study indicated that imipenem (carbapenem) and amikacin are the antibiotic of choice for the treatment of multi-drug resistant urinary tract infections caused by ESBL-producing K. pneumoniae. The third and fourth generation cephalosporins and nitrofurantoin are suitable for the treatment of urinary tract infections due to non-ESBL-producing K. pneumoniae. Rational use of antibiotics and evidence based antibiotic prescription will help to control the spread of resistance by ESBL-producing K. pneumoniae. There is the need to intensify research in the use of natural products to treat multi-drug resistant urinary tract infections emanating from ESBL-producing K. pneumoniae
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