Microbiology Research Journal International

Background: Several anthropogenic activities have led to serious health and environmental problems as a result of releasing different contaminants in to the ecosystem including heavy metals. This called for search of possible methods that could be used to ameliorate the environment and biosorption was found to be promising.

Aim: The potential of Oscillatoria sp. was investigated with a view to determining its suitability in the biosorption of Cr²⁺ and Pb²⁺.

Place and duration of Study: The study was conducted at the Research Laboratory, Department of Microbiology, Usmanu Danfodiyo University Sokoto, between January and July, 2016.

Methodology: Samples of the algal species were collected from an irrigation site at Kwalkwalawa area of Usmanu Danfodiyo University Sokoto. The samples were dried and powdered for biosorption studies. Biosorbents were prepared and used for sorption of heavy metals at different time and substrate concentration.

Results: It was observed that Oscillatoria sp. biomass could adsorb appreciable amounts of the metals in a dose and contact time-dependent manner. At lower biomass doses, lower rates were recorded with a mean of 0.002 mg/g and increased to 0.1mg/g when 2 g and 5 g biomass were used respectively in both cases of the metals uptake. Based on contact time, Cr²⁺ uptake was initially slow with mean value of 0.002 mg/g for the first 50 minutes and rapidly increased to optimum at 60 minutes of contact time. For Pb²⁺ however, uptake was rapid with peak value of 0.1mg/g for the first 20 minutes. The uptake drastically decreased at 35 and 50 minutes and equilibrium was attained at 60 minutes of contact time.

Conclusion: Oscillatoria sp. has the potentials of Cr²⁺ and Pb²⁺ uptake and thus suitable for biosorption of low heavy metals concentrations.

Aims: This research was designed to evaluate the phytochemicals present in the leaf extracts of Chromolaena odorata L. and their antimicrobial activities.

Methodology: Dried leaves of C. odorata were pulverized and subjected to ethanolic and aqueous extraction. The extracts were qualitatively and quantitatively screened for phytochemicals using standard methods. The inhibitory activity of the leaf extracts were evaluated against clinical pathogens; Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumoniae, Proteus mirabilis and Candida albicans using agar well diffusion technique at 100 mg/mL and 200 mg/mL concentrations.

Results: The ethanolic extract of C. odorata had a better percentage yield of 5.49 g, followed by aqueous extract (3.5 g). The phytochemical screening conducted on the extracts revealed the presence of flavonoid, alkaloid, saponin, cardiac glycoside, steroids, tannins and terpenoids. The ethanolic extract exhibited better antimicrobial activity on S. typhi, S. aureus, E. coli, Ps. aeruginosa and C. albicans compared to the aqueous extract. This could be as a result of the higher extraction capability of the ethanol to penetrate easily into the cellular membrane and dissolve the intracellular inclusions from the plant materials than the aqueous solvent. The zones of inhibition of ethanolic extract at 100 mg/mL ranges from 2.33±0.33 mm to 9.50±0.36 mm with the lowest efficacy observed on P. mirabilis and highest on S. aureus. S. typhi was susceptible to the aqueous extract of the plant at this concentration with inhibitory zone of 4.00±0.00 mm. The ethanolic extract of the plant was also effective against C. albicans with inhibitory zone of 4.17±0.17 mm at 100 mg/mL. Chloramphenicol inhibited all the test bacteria with the highest efficacy on E. coli (16.33±0.03 mm) and ketoconazole at 25 mg/mL had a better antifungal activity on C. albicans compared to the observed antifungal activities of the aqueous and ethanolic extracts of C. odorata at 100 mg/mL. Furthermore, the test organisms were more susceptible to the aqueous and ethanolic extracts of C. odorata at 200 mg/mL with zones of inhibition ranging from 3.23±0.15 mm to 12.33±0.33 mm. The lowest being observed on E.coli and highest on S. typhi (ethanolic extract). K. Pneumoniae and P. mirabilis were resistant to the aqueous extract of C. odorata. All the test bacteria were susceptible to the aqueous and ethanolic extracts of C. odorata at 200 mg/mL extracts concentration. Moreover, C. albicans was susceptible to the inhibitory effect of C. odorata at this concentration with inhibitory zones of 3.00±0.00 mm and 5.33±0.33 mm on aqueous and ethanolic extracts respectively.

Conclusion: The findings from this study revealed the antimicrobial activities of C. odorata on the test pathogens which are in close proximity in comparison with the synthetic antimicrobial agents and thus upon purification, can be harnessed as a lead for the development of natural products derived antimicrobials in drug discovery against infections caused by these human pathogens evaluated in this study.

This study was carried out to measure the optimum condition for Bacteriocin production by Lactobacillus plantarum. Bacteriocin production with the candidate bacterium Lactobacillus plantarum NRIC 0383) was optimized by varying the incubation temperature and adjusting the pH of the production medium, whilst estimating bacteriocin production in terms of the antagonistic activity (zone of inhibition mm) against bacteria pathogens of selected vegetables using the well diffusion assay. Bacteriocin production was highest at temperatures of 30 and 35^oC and pH values of 6.0 and 6.5, further decrease or increase in temperature and pH values markedly decreased bacteriocin production. Increase in bacteriocin production as regards time was observed between the 24^th -36^th hours of incubation, contrariwise increased incubation time was accompanied by a decline in bacteriocin production. The present study provides detailed information on bacteriocin production (estimated in terms of the antagonistic activity) as it relates to specific isolates strains.

Aim: Effect of fermentation on nutrient and anti-nutrient contents of defatted and un-defatted African bush mango seeds.

Study Design: Ground African bush mango seeds used in this study were divided into two portions; A, and B. Portion A was defatted while portion B was not defatted; both portions were fermented.

Place and Duration of Study: Department of Microbiology and Chemistry Department, Federal University of Technology Akure, Ondo State between November 2017 and July 2018.

Methodology: Microbial analysis was carried out using pour plate technique. The temperature, pH and total titratable acidity were monitored throughout the fermenting period. Proximate, mineral and anti-nutrient contents of the samples were carried out using standard methods.

Results: Seventeen microorganisms comprising 11 bacteria and 6 molds were isolated and identified as; Staphylococcus aureus, Bacillus subtilis, B. cereus, S. epidermis, B. licheniformis, Micrococcus luteus, Proteus vulgaris, Enterococcus faecalis, Lactobacillus fermentum, L. plantarum, L. brevis, Aspergillus clavatus, A. flavus, A. niger, Rhizopus stolonifer, Penicillium chrysogenum and A. fumigatus. The pH and TTA values reduced and increased respectively while the temperature varied significantly as the fermentation day increases. The non-defatted fermented sample showed increase in protein (10.34-12.09%), moisture (6.98-7.84%) and carbohydrate contents (24.98-29.20%); while there was a reduction in the ash (3.91-2.93%), fibre (1.55-1.30%) and fat (52.24-46.64%) contents. The defatted fermented sample showed an increase in the protein content (17.39-26.44%) while there was a reduction in the moisture (26.60-26.46%), carbohydrate (41.02-38.96%) ash (4.07-3.01%), fat (9.44-4.02%) and fibre contents (1.48-1.11%). The mineral composition of the fermented samples increased significantly when compared to the raw samples. The anti-nutrient content of the samples decreased significantly with fermentation.

Conclusion: This study revealed that African bush mango seeds can be defatted and fermented to produce food of enhanced nutritional value.

Aims: To investigate carriage and contamination rates of chicken broiler meat, the factors that are associated with Campylobacter spp. colonization and its phenotypic and genotypic antimicrobial resistance from Thika small-scale poultry farms.

Study Design: The study design was cross-sectional and laboratory based, it employed simple random sampling across 18 small-scale farms.

Site and Duration of Study: The study was conducted between August and December 2017 at Thika sub-county, a town located 42 Km North East of Nairobi.

Methodology: One hundred and eighty five cloaca swab samples from live broilers and 158 neck swab samples from broiler carcasses were collected. Isolates were obtained by plating method using mCCDA, conventional methods and duplex PCR were used for the isolation and identification of Campylobacter species.

Results: Carriage prevalence was at 15.67%, significantly (P = .000) lower than contamination prevalence detected at 30.37%. While the overall Campylobacter spp. prevalence was 22.45%.  Risk of Campylobacter colonization in the flock doubled in feeding broilers with chicken waste and older poultry, at (OR: 2.57, 95% CI: 0.19 - 34.47) and (OR: 2.00, 95% CI: 0.312 - 12.84) respectively. The Campylobacter spp. were resistant (P < .05) against Ciprofloxacin, Streptomycin, and Trimethoprim between carriage and contamination. MDR was 79.22%; XDR was 12.98% while no PDR recorded.

Conclusion: Broilers in Thika region are potentially important source of human infection and possible continuity of infection from the threat posed by Campylobacter carrier broilers. Presence of sulI and dhfr genes with high resistance observed for quinolones, sulfonamides, ß-lactams and trimethoprim, thus posing a major public health problem for consumers of poultry products.