Open Access Short Research Article
Aims: To determine the antimicrobial potentials of leaves, roots and barks of Vitellaria paradoxa “Shea-nut tree” used in traditional medicine for treatment of stomach ache and control of diarrhea.
Place and Duration of Study: Department of Microbiology, Federal University of Agriculture Abeokuta, Ogun State, P.M.B 2240, Nigeria, between August 2010 and May 2011.
Methodology: The leaves, roots and leaves were extracted by four solvents: methanol, omidun, sterile-omidun and aqueous. These extracts were tested for antimicrobial activities at different concentrations (100 mg/ml, 50 mg/ml and 25 mg/ml respectively) against some gastroenteric organisms using the disc diffusion assay. The test organisms used are typed culture E. coli ATCC 25922 and clinically isolated Enteropathogenic E. coli, Enterohaermohargic E. coli, Salmonella typhi and Shigella flexneri. The extractants served as negative control while loperamide antibiotics served as positive control.
Results: Generally, all the extracts exhibited varying antimicrobial activities against the test organisms with most of them exhibiting low Minimum Inhibitory Concentration (MIC). There was significant difference (p<0.05) in the effects of each of the extracts when used at different concentrations. The higher the concentration of extract, the wider the zone of inhibition. Methanol extracts showed the highest potency (19.0 mm for bark and 6.67 mm for root) followed by omidun extracts (17.33 for bark and 4.67 mm for root). Aqueous and sterile omidun extracts produced low inhibition at high concentration and no inhibition at low concentrations. At 100 mg/ml methanol extraction, the bark of Shea butter tree gave the highest potency (13.67–19.00 mm) followed by extracts of leaves (11.33-16.70 mm) while the extracts of roots had the lowest potency (6.67-17.00 mm).
Conclusion: Extracts of this plant parts have antimicrobial effects on the tested enteric bacteria, hence serve as potential therapeutic agent against diarrhea.
Open Access Original Research Article
Aims: To assess the potential health risks of fresh produce grown on irrigated soils treated with manure in Kano State, a large produce region in Nigeria.
Methodology: Fresh produce irrigated with wastewater on manure treated soils were assessed for the prevalence, serotype distribution and toxigenicity of Escherichia coli O157, Salmonella spp and Vibrio cholerae in a large produce region in Nigeria. A total of 230 samples obtained from five designated produce locations were examined using selective isolation method with prior enrichment. Fresh produce comprised carrots, cabbage, cucumber, lettuce, tomatoes, spinach, green peas and spring onions. Suspect isolates were identified and characterized by conventional biochemical methods and Microbact 24E (Oxoid, UK) kit. Confirmed isolates were serotyped and E. coli O157 and Vibrio cholerae O1 were assayed for their toxigenic potentials using the Reverse Passive Latex Agglutination kit. The enterotoxigenicity of Salmonella spp was determined by detection of stn gene using polymerase chain reaction (PCR) techniques.
Results: Results obtained showed that overall, Salmonella spp and Escherichia coli O157 had the highest prevalence of 17.0% and 10.9%, respectively. Both were most commonly detected from fresh produce. The serotypes of Salmonella detected include Salmonella typhi (51.3%), Salmonella paratyhpi (20.5%) and Salmonella typhimurium (28.2%); strains of Vibrio cholerae O1 detected include Vibrio cholerae O1 of the Ogawa, Inaba and the Hikojima serotypes.
Conclusion: The use of untreated irrigation water in vegetable production represents a significant route of transmission of diarrheal pathogen to humans and hence represents a public health risk. We recommend proper and adequate wastewater treatment before use.
Open Access Original Research Article
The popular food, dairy products like curds are consumed by many people in its various forms in Bangladesh. Infact, these different types of curds are made without real respect for basic standards of technology and hygiene. This situation will be improved if lactic ferments are well-identified and their synergy taken into consideration. Not much information has been reported about the Lactobacilli species responsible for curd production in Bangladesh. In this context, this study was conducted to identify and characterize lactic acid bacteria in curds to provide scientific data needed for improvement of the fermented product. Twenty samples were collected from the producers of curds in the supermarket of Shaheb Bazar, Rajshahi. The culture media used were Czapek Dox (pH 5.3), M17, MRS and nutrient broth and agar for the investigation of lactic acid bacteria. The identified lactic acid bacteria were Lactobacilli including Lactobacillus casei (sample 1), Lactobacillus delbrueckii (sample 3), Lactobacillus plantarum(sample 4) and Lactobacillus helveticus (sample 6) based on morphological characteristics, catalase activities, milk coagulation, growth at different temperature, growth in medium with different NaCl concentrations, growth at different pH, carbohydrate fermentation profiles, exopolysaccharides production, resistance to antibiotics and other biochemical tests. The results of this work will help in the production of dairy products with better quality and longer shelf-life. The isolation of lactic acid bacteria particularlyLactobacilli could be a good tool for information to improve the characteristics of curds and hygienic quality of the dairy products.
Open Access Original Research Article
Aims: To isolate bacterial strains from chickpea rhizospheric soil and nodules, to characterize and identify potential bacterial strains by using 16S rRNA gene sequencing.
Place and Duration of Study: Department of Soil Science & SWC, PMAS, Arid Agriculture University, Rawalpindi Pakistan between July 2010 and July 2011.
Background: Plant growth promoting rhizobacteria are being preferred nowadays as inoculants for influencing crops via multiple direct or indirect mechanisms but screening to find out the effective PGPR strains is one of the crucial steps. This research is aimed at keeping in view their potential for phosphate solubilization, indole acetic acid and ammonia production.
Methodology: Extensive survey was carried out in Pothwar (District, Rawalpindi, Attock and Chakwal) for collection of chickpea rhizospheric soil and root nodules. The isolation of rhizospheric soil bacteria was performed by using dilution plate technique while the root nodules bacteria were isolated on yeast extract mannitol agar supplemented with congo red. Ten bacterial strains designated as AM-1 to AM10 were isolated, purified and characterized for phosphate solubilization, indole acetic acid (IAA) and ammonia production. These bacterial strains were identified as belonging to species of Bacillus, Enterobacter, Pseudomonas, Rhizobium, Sphingobacterium, Pantoea and Chryseobacterium. All bacterial strains solubilized phosphate and produced IAA. Two bacterial strains AM-5 (Sphingobacterium canadense) and AM-4 (Rhizobium pusense) solubilized the maximum amount of phosphate i.e. 273.84 µg ml-1 and 262.83 µg ml-1 respectively with a significant pH drop from 7 to 2.67. These strains proved positive for ammonia production. Six most potential and identified strains were selected on the basis of plant growth promoting activities.
Conclusion: AM-4 (Rhizobium pusense) and AM-5 (Sphingobacterium canadense) are efficient strains and there is a need of inoculation experiments under control and field conditions to use these stains as biofertilizer to enhance the growth and productivity of the chickpea.
Open Access Original Research Article
Objective: Infections with Salmonella resistance to extended-spectrum cephalosporins threaten the efficacy of drugs for treating samonellosis. So the aim of this study was to characterize the ESBL (Extended Spectrum β-lactamase)-producing Salmonella species.
Methods: The ESBL-producers were extensively characterized using antibiogram, double disc diffusion synergy test, plasmid profiling, PCR, pulsed-field gel electrophoresis (PFGE) and conjugation experiments.
Results: Of the 200 Salmonella strains, n=8 were found to be ESBL-producers and these belonged to only two serogroups, Salmonella Group B (n=4) and Salmonella Group G (n=4). Most of the ESBL-positive strains were found to be resistant to third and fourth-generation cephalosporins and monobactams. Plasmid profiling indicated that n=6 and n=2 of the ESBL-producing strains harbored a 62-MDa and a 90-MDa plasmid, respectively. The PCR analysis revealed that blaTEM (β-lactamase Enzyme TEM Producing Gene) (n=6) was most predominant gene, followed by the blaOXA (β-lactamase Enzyme OXA Producing Gene) (n=4), blaSHV (β-lactamase Enzyme SHV Producing Gene) (n=2) and blaCTX-M-1 (β-lactamase Enzyme CTX-M-1 Producing Gene) (n=2) genes. Fifty percent (n=4) of the strains were positive for the int1 gene. The PFGE analysis revealed that almost similar clones were disseminated within the ESBL-producing strains and the non-ESBL-producing strains. The conjugation study revealed that the 62-MDa plasmid was transferred to E. coli K-12 and contained the blaTEM, blaOXA, blaCTX-M-1 and int1 genes.
Conclusion: The emergence of ESBL-producing Salmonella is of great concern and horizontal gene transfer plays an important role in the spread of ESBL.
Open Access Review Article
Purpose of Review: There is still controversy whether EBV could be a causative agent as opposed to an innocent bystander in the pathogenesis of multiple sclerosis (MS). We aimed to review main studies which were investigated the subject to reveal whether the presence of a possible latent or active infection with Epstein-Barr Virus (EBV) of people with MS could actually play a role in the development of the disease. This review summarizes current knowledge on the association of EBV and MS.
Summary and Results: Multiple sclerosis (MS) is a demyelinating condition affecting the central nervous system. The etiology and pathogenesis of MS are unknown, but environmental agents and genetic susceptibility are likely to be involved. From the very early days of MS discovery, infections have been proposed to be the underlying causes of disease initiation. This assumption led to the development of the first FDA-approved immune-modulatory treatment for MS, Interferon-beta (IFN-b), known with its antiviral activities. It has been pointed out that a link between delayed infection with EBV and the development of MS is compatible with many unusual epidemiological features of the disease EBV infects more than 90% of all humans, most of whom remain healthy. In contrast, 99% of MS patients have evidence of prior infection with EBV. EBV infects resting B-lymphocytes, immortalizing them into long-lived memory B-cells that survive largely undetected by the immune system in the peripheral circulation. MS patients show elevated titers to EBV years before developing any neurologic symptoms. Postmortem pathologic analysis of brains of patients with MS has revealed diffuse EBV-associated B-cell dysregulation in all forms of MS. Theories of pathogenesis of EBV in MS include antigenic mimicry, immortalization of B-cell clones, and cytotoxic T-cell dysfunction against virally infected B cells. This article reviews the existing evidence of the relationship between EBV and MS.