Open Access Original Research Article

Antifungal Activity of Copper, Zinc and Potassium Compounds on Mycelial Growth and Conidial Germination of Fusarium solani f. sp. piperis

Renata Aparecida Ahnert dos Santos, Verônica D’Addazio, João Vitor Garcia Silva, Antelmo Ralph Falqueto, Marcelo Barreto da Silva, Edilson Romais Schmildt, Adriano Alves Fernandes

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/mrji/2019/v29i630179

Fusariosis is a disease that causes economic damage to black pepper (Piper nigrum L.) producers. Despite being a major disease, there is no record of efficient chemical control. Thus, the objective was to evaluate the antifungal activity of copper, zinc and potassium compounds in mycelial growth and conidial germination of Fusarium solani f. sp. piperis in vitro. For inoculation in PDA (Potato Dextrose Agar) medium, 7 mm discs from the pure culture were transferred to Petri dishes. The plates were incubated at 25ºC in a biochemical oxygen demand (BOD) chamber, with photoperiod of 12 h, for 15 days. Micronutrients were supplied as sulfates, CuSO4 (copper sulfate) and ZnSO4 (zinc sulfate), at concentrations of 1, 5, 10, 15 and 20 mmol/L. Potassium macronutrient (K) was supplied as KCl (potassium chloride) at concentrations of 30, 60, 90,120 and 150 mmol/L. The experiment was performed using a completely randomized design with 6 treatments and ten replications. CuSO4 showed fungicidal effect at concentrations of 10, 15 and 20 mmol/L. For ZnSO4 mycelial growth was completely inhibited at concentrations of 15 and 20 mmol/L. There was no inhibition or reduction of fungal growth in the presence of K. Copper and zinc at minimal concentrations were efficient in controlling mycelial growth and inhibition of spore germination of F. solani f. sp. piperis. In contrast, potassium did not exert fungicidal or fungistatic effect on the fungus.

Open Access Original Research Article

Influence of Sublethal Temperatures on Some Spore-forming and Vegetative Foodborne Bacteria and Impact on Hygienic Quality of the “Foléré” (Hibiscus sabdariffa) Beverage

James Ronald Bayoï, Roger Darman Djoulde, Flaure Essoung Ehawa, Francois-Xavier Etoa

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/mrji/2019/v29i630180

Aims: “Foléré” beverage is a refreshing locally made drink much appreciated by the populations of the hottest parts of Cameroon. This paper aims at investigating microbial contamination of “Foléré” beverage and highlights impact of the sublethal temperatures on the hygienic quality the beverage.

Study Design: Design used for describing physicochemical and microbial profile is a random sampling and for impact of sublethal temperature on hygienic quality, we used food matrix simulations.

Place and Duration of Study: Samples: Local markets, between August 2018 and June 2019.

Methodology: The sample pH and soluble solids content were recorded using portables devices. Microbial analysis focused on total aerobic mesophilic bacteria, Escherichia coli, and spore-forming bacteria were determined according to accredited culture methods. Acidic “Foléré” beverage produced by an artisanal processing was sterilized and inoculated by Bacillus cereus T spores and Escherichia coli ATCC 25922 cells thermally stressed by pre-incubation at 10°C, 45°C, 50°C or 60°C for 45 min, 90 min and 180 min. The recovery method was used to determine acid pH resistance of both bacteria before and after sublethal thermal processing.

Results: “Foléré” beverage is of poor hygienic quality according to standards, despite its very low pH (2.01). Beverages at pH 2.01 and inoculated by each one of referenced bacteria indicated that the samples which contained thermally stressed bacteria were worse hygienic quality than the same ones which contaminated with unstressed bacteria. Some of recovery percentages of bacteria thermally stressed were significantly higher (P =.05) than those of same bacteria thermally unstressed after acid treatments. That phenomenon was called thermal-induced bacterial acid resistance.

Conclusion: it appeared that some sublethal cold and heat shock treatments (10°C/45 min, 45°C/45 min, 50°C/90 min and 180 min) could negatively affect food quality. So, the control of emergence and evolution of stress-resistant bacteria in food could help to improve food safety.

Open Access Original Research Article

Bioassay of Lemongrass on Fungi Pathogen Associated with Cassava Tubers Rot in Farin Gada Market, Jos

W. C. John, O. Oke, M. Ishaya, O. O. Olorundare, N. Janfa, M. J. Mafuyai

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/mrji/2019/v29i630181

The aim of this study was to determine the effects of Lemongrass on fungal pathogen associated with cassava tuber rot. The study was carried out in the biology laboratory of the Federal College of Forestry Jos, Plateau state from March to May, 2019. Rotten and healthy cassava tubers were collected separately from Farin-Gada market Jos, fungi species were isolated from rotten cassava tubers by direct inoculation of the spoiled part on sterile Potato Dextrose Agar medium and incubated for 3-5 days, the isolated fungi were identified microscopically and macroscopically. The identified fungi were used for pathogenicity test. The antifungal effect of different concentrations of ethanol extract of lemongrass was investigated. Data collected were analyzed using one way ANOVA and the means were separated using Least Significant Difference (LSD) at (p≥0.05). The fungi isolated include, Fusarium sp, Penicillium sp, Geotrichum candidum, and Aspergillus flavus. The frequency of occurrence of the isolated fungi indicated Fusarium sp, Penicillium sp, Geotrichum candidum, and Aspergillus flavus had 30, 15, 35 and 20% respectively. 20 mL of the tested extract gave the highest inhibition of 19.07, 20.57, 18.17 mL and 18.00 mL on Fusarium spp, Penicillium spp, Geotrichum candidum and Aspergillus flavus respectively. At the 5th day of incubation the results of the pathogenicity showed that Aspergillus flavus gives the highest deterioration of 9.17 mm. The length of deterioration showed significant difference. The lemongrass extract indicated anti-fungal effect on the fungal isolates, therefore could be used to control cassava tuber rot caused by fungi.

Open Access Original Research Article

Detection of Oxacillin (Methicillin)-resistant Staphylococcus aureus Isolated from a Tertiary-care Hospital, Georgetown, Guyana

Paul Cheddie, Drovashti Seepersaud, Tereasia Ramlochan

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/mrji/2019/v29i630182

Background and Aim: Methicillin-resistant Staphylocccus aureus (MRSA) continues to be a major problem globally. Previous data had suggested that the prevalence of MRSA infections in the tertiary hospital setting was 51%. The aim of this study was to conduct a point prevalence survey of MRSA infections occurring at a tertiary-care hospital in Georgetown, Guyana, and to determine to what extent methicillin-resistance was occurring among Staphylococcus aureus isolates utilising the minimum inhibitory concentration (MIC) data.

Study Design: This study was based on a prospective, analytical design.

Place and Duration of Study: Microbiology department, Georgetown Public Hospital Corporation (GPHC), and Department of Medical Technology, University of Guyana, between May 2019 and July 2019.

Methodology: A total of 101 consecutive, non-repetitive, laboratory-identified MRSA and methicillin-susceptible Staphylococcus aureus (MSSA) isolates were tested using an oxacillin broth microdilution method.

Results: We found that 65.4% of Staphylococcus aureus were oxacillin (methicillin) resistant with a majority of the isolates being high level oxacillin resistant strains (i.e., MICs > 256 μg/ml) (84.85%). Most of the resistant isolates were collected from patients admitted to medical and surgical wards. Conclusion: Methicillin-resistance continues to be a major problem in the hospital setting and conventional techniques are unlikely to identify all of the potentially resistant isolates.

Open Access Original Research Article

Risk Factors and Prevalence for Latent Tuberculosis Infection among Health Care Workers in Al-Quwayiyah General Hospital Riyadh, KSA

Enas Sh. Khater, Khalid H. M. Abdo

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/mrji/2019/v29i630183

Background: All health care facilities should intensify TB screening and encourage treatment of latent tuberculosis infection (LTBI) among Healthcare workers (HCWs) to prevent progression to tuberculosis (TB) disease.

Aim: This study was conducted to determine the prevalence and associated risk factors of LTBI among HCWs in Al Quwayiyah General hospital as well as to compare the performance of QuantiFERON-TB Gold Plus (QFT-Plus) to TST in identifying LTBI.

Methods: A cross sectional study and prospective cohort study was performed from January to July 2019 in Al Quwayiyah General hospital involving a total of 718 HCWs. questionnaire with socio-demographic data and work history was filled, and both tests were done TST and QFT test for each Healthcare worker.

Results: The study showed that The prevalence of latent tuberculosis diagnosed was 9.05% and 9.19% using QFT-Plus and TST respectively. Only 26 (3.62%) subjects were positive for both tests whereas 131 (18.25%) were positive by either test. Comparing the results of the QFT-Plus with those of the TST, both tests had a significant total agreement of 88.8. Negative concordance comprised 85.37% of the results, and positive concordance comprised 3.62%. However, positive TST but negative QFT-Plus comprised 5.57% of the results, and negative TST but positive QFT-Plus comprised 5.43%. The association between risk factors and QFT-Plus test results in the studied groups showed that the smoking, health status, immunosuppresion, housing, occupation, contact T.B. at work place, past history of TB and diabetes mellitus appear as significant risk factors. The association between the studied risk factors and TST in the studied groups showed sig­nificant difference noted for smoking, BCG vaccination, immunosuppresion, housing, occupation, contact T.B. at work place, past history of TB and diabetes mellitus.

Conclusion: The prevalence of latent tuberculosis diagnosed was 9.05% and 9.19% using QFT-Plus and TST respectively. Testing of HCWs at hire and periodically can help in the detection of LTBI Large scale study is recommended to confirm such findings in Saudi Arabia, also the use of Quantiferon for detection of LTBI beside using TST is recommended as it reduce the false positive reports by TST and is not affected by prior BCG status.

Open Access Original Research Article

Improvement of Faba Bean Production in Saltaffected Soils by Rhizobium leguminosarum bv. viciae Inoculation and Phosphorus Application

Ibrahim El-Akhdar

Microbiology Research Journal International, Page 1-15
DOI: 10.9734/mrji/2019/v29i630184

Faba bean (Vicia faba L.) represents a major source of protein for animal and human nutrition, and provides several benefits such as improved soil quality. The Giza cultivar 87 (Vicia faba L.) was evaluated in three different salinity levels (6.9, 8.7 and 14.8 dSm-1) during two successive cropping seasons (2016-2017 and 2017-2018). The experiment was designed to analyze effect of soil salinity on nitrogen fixation, protein, chemical composition and crop productivity (for both grain and straw). Three phosphorus levels and inoculation with Rhizobium leguminosarum bv. viciae were investigated to improve the growth of Vicia faba L under these conditions. Soil salinity levels reduced the grain number and straw weight of plants. Moreover, yield reductions were associated with increasing soil salinity levels confirming salinity effects on faba bean productivity. Salinity induced a significant decreased in all plant growth parameters, plant chlorophyll and grains proteins, as well as increased Na% of faba bean plants. The plants treated with R. leguminosarum bv. viciae showed significant increase in growth traits such as plant length (%), plant fresh weight (%), protein, N-content and dry weight. On the other hand, the dual treatments with R. leguminosarum bv. viciae plus phosphorus gave a great results compared with inoculation or phosphorus alone. Symbiotic nitrogen fixation inoculation enhanced the growth and yield parameters.