Open Access Original Research Article

Synergism of Entomopathogenic Organisms Associated with Zonocerus variegatus

F. O. Omoya, B. A. Kelly

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/MRJI/2017/28863

Aim: Entomopathogenic organisms were investigated for their lethal ability, minimum lethal concentration and synergy against caged short-horned grasshoppers (Zonocerus variegatus).

Place and Duration of Study: Study was carried out in the Department of Biological Sciences, Wesley University, Ondo, Nigeria between March and August, 2016.

Methodology: Adult Z. variegatus of both sexes were caught by sweep nets from the university cassava (Manihot esculenta) farm, divided into batches of 10, fed and observed for the onset of disease symptoms such as lethargy, colour change, abnormal outgrowths and death. Organisms were isolated from the diseased insects. Pathogenicity test was carried out on all the isolated organisms. Synergism was examined amongst the organisms by challenging the insects with more than one entomopathogens at the same time.

Results: Duncan’s Multiple Range Test was used for the estimation of means. The ‘t’ value was tested at 95% confidence interval. 10 insects were included in each sample batch and each test were carried out in triplicates (n = 3), Bacillus subtilis, Beauvaria bassiana and Aspergillus niger were able to induce pathogenicity on the insects. B. bassiana caused death in 8.67±0.58 insects, A. niger was lethal on 7.33±0.58 while B. subtilis was lethal on 8.67±0.29. The minimum lethal concentration (MLC) of the organisms when used to challenge the insects are 5.0 ×104 spore forming units per milliliter (sfu/ml) for B. bassiana as it causes death in 6.33±0.58 out of the 10 insects used. 8.0 ×108 sfu/ml of A. niger causes death in 6.67±0.58 and 6.0 ×106 cfu/ml for B. subtilis. Synergistic test carried out shows greater entomopathogenic effect when a bacteria-fungi formulation was used compared to when a fungi-fungi formulation was used. ‘A. niger B. bassiana’ formulation caused 5.33±0.58b death while the formulation using A. niger – B. subtilis and B. bassiana – B. subtilis caused 6.33±0.58c and 6.67±0.58cd lethal cases respectively.

Conclusion: B. subtilis, B. bassiana and A. niger isolated from diseased Z. variegatus in this study possess entomopathogenic ability. They can be further studied for the enhancement of their entomopathogenicity, biosafety, most suitable method of delivery and mass production.

Open Access Original Research Article

Microbiological Characteristics of Traditionally Fermented Milk (Roub) Manufactured and Sold in Khartoum State, Sudan

Mohamed Osman Mohamed Abdalla, Safinaz Adil Sir El-Khatem Osman

Microbiology Research Journal International, Page 1-6
DOI: 10.9734/MRJI/2017/33150

Aims: This study was conducted to evaluate the microbiological quality of roub collected from different areas in Khartoum State, Sudan during the storage period.

Methodology: Thirty roub samples were collected from Khartoum, Khartoum North and Omdurman areas in sterile polyethylene bags, preserved in sample containers in ice (4ºC) and transported to the laboratory for analysis.  Microbiological [total viable bacteria (TVB), coliform bacteria, lactobacilli, yeasts and moulds] characteristics were determined at 1, 7, 14 and 20-day intervals.

Results: The results showed that all microorganisms tested (except coliform bacteria) were significantly (P<0.001) affected by the area from which samples were collected, with TVB being high in Omdurman (Log 6.35±1.027 cfu/gm), while lactobacilli (Log 7.75±0.775 cfu/gm) and yeasts and moulds (Log 7.49±0.685 cfu/gm) were high in Khartoum North, and coliform bacteria were high in Khartoum (Log 6.29±2.497 cfu/gm). The storage period significantly (P<0.001) affected all microorganisms tested. Coliform bacteria and lactobacilli were significantly (P<0.001) affected by the storage period in samples collected from Khartoum, while only coliform bacteria were significantly (P<0.001) affected in samples collected from Khartoum North. All microorganisms were significantly (P<0.001) affected by the storage period in samples collected from Omdurman except coliform bacteria which were not detected.

Conclusion: It is concluded that there was a significant variation in microbial contamination of the product collected from different areas in Khartoum State, as well as the storage period affecting the microbial count of the product.

Open Access Original Research Article

Influence of Physicochemical Parameters on Mosquito Larvicidal Potency of Bacillus subtilis Isolated from Musca domestica (Linn) Cadavers in Nigeria

F. O. Omoya, B. E. Boboye

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/MRJI/2017/31806

Aims: Biological control method is one of the methods used in controlling the menace of insect pest because it posed no threat to the human health and less damage to the environment. This study therefore assessed the effect of selected physicochemical parameters on the larvicidal potency of Bacillus subtilis(Berg) on Anopheles arabiensis (Linn) mosquito larvae.

Study Design: The physicochemical parameters were considered for this study include; pH, concentration, temperature, turbidity and sunlight. 

Place and Duration of Study: This research was carried out in the Department of Microbiology Federal University of Technology, Akure, Nigeria, between May 2013 and September 2013.

Methodology: Bacillus subtilis were isolated from cadavers of Musca domestica and it larvicidal potency on Anopheles arabiensis (Linn) mosquito larvae was tested by varying values of each of physicochemical parameters on both the 2nd and 4th instars of laboratory reared Anopheles arabiensis using standard methods.

Results: A mortality of 30% was recorded at pH 4.0 while at pH 9.0 higher percentage mortality (81%) was observed on the second instars larvae. Five temperatures of 16°C, 18°C, 24°C, 34°C and 40°C representing four major temperature ranges in southwestern Nigeria (night, morning, afternoon and evening) and control temperature (28±2°C) revealed significant variation in the percentage mortality of mosquito larvae. Varying concentrations of Bacillus subtilis cells showed that the larvicidal activity of this bacterium was best displayed at higher concentrations. The water turbidity and sunlight also affected the effectiveness of the larvicidal activity.

Conclusion: This study revealed that Bacillus subtilis was able to demonstrate high larvicidal activity against Anopheles arabiensis larvae despite the varied physicochemical parameters. However, further work may be needed to validate reliability.

Open Access Original Research Article

An in-vitro Analysis of the Antioxidant and Antimicrobial Properties of the Methanol Extract of Hypoxis hemerocallideacorm (MEHHC) from Botswana

N. Mannathoko, S. George, S. Souda, K. Chabaesele, I. Goercke

Microbiology Research Journal International, Page 1-12
DOI: 10.9734/MRJI/2017/32936

Aims: To evaluate the antimicrobial and antioxidant activity of the methanol extract of Hypoxis hemerocallidea corm (MEHHC) with different assays.

Study Design: In vitro evaluation of antibacterial and antioxidant activities of the MEHHC.

Location and Duration of Study: Department of Biological Sciences (Faculty of Sciences) and Faculty of Health Sciences, University of Botswana from Jan.2015 to Sep. 2016.

Methodology: The MEHHC was prepared and evaluated for total phenolic content (TPC) and antioxidant properties with DPPH and ABTS methods. Phytochemical screening was conducted to detect bioactive constituents. Antimicrobial activity was determined with diffusion assays, minimum inhibitory concentration and minimum bactericidal concentration assays.

Results: The MEHHC exhibited antioxidant activity and the ability to scavenge DPPH radicals. A relatively high TPC was observed and there was a strong association between antioxidative activities and phenolic compounds (R=0.871), suggesting that the constituent phenolic compounds may confer the antioxidative activities to the MEHHC. The MEHHC exhibited anti-fungal activity against C. albicans and variable antibacterial activity against the Gram positive and Gram negative bacteria. There was more pronounced activity against the tested Gram positive bacteria, particularly S. aureus (including the MRSA ATCC 430043 strain) whereas E. coliS. typhimurium and K. pneumoniae displayed the lowest susceptibility to the MEHHC.

Conclusion: The results indicate that the MEHHC has considerable antioxidant and anti-microbial properties. Potentially the MEHHC is appropriate for pharmaceutical purposes both as an antioxidant and antimicrobial agent.

Open Access Original Research Article

Risk Factors Associated with Salmonella Contamination of Chicken Carcases in Traditional Slaughterhouses in Morocco

A. Chaiba, F. Rhazi Filali

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/MRJI/2017/33013

Aim: The objective of this study was to identify the risk factors for Salmonella spp. contamination of Moroccan chicken carcases during slaughtering. Sixty four traditional slaughter houses were studied from  October  2014 to June  2016  in Ouarzazate (Morocco).

Methodology: A questionnaire was submitted to the slaughterers and samples of breast skin were taken to assess the Salmonella spp. status of chicken carcases.

Results: 18.75% of the chicken batches were contaminated with Salmonella spp., with Salmonella Agona and Salmonella Kentucky as the two main serovars. Salmonella spp. contamination of the birds before slaughtering (OR = 12), long stay of birds in the slaughterhouse before slaughtering (OR = 9) and reusing of the scalding water for a long time (OR = 6) increased the risk of Salmonella contamination of carcasses.  But, washing carcase after defeathering (OR = 7.67) and cleaning of the tools and cutting table after the previous evisceration (OR = 4.7) decreased this risk.

Conclusion: These Risk factors were mostly related to the hygienic status of the live birds and sanitary practices observed at traditional slaughterhouses. The training and sensitization of slaughterers and the implementation of preventive hygiene measures can reduce the risk of contamination.