Open Access Short communication

Detection of Multiple Cry Genes in Bacillus thuringiensis Isolated from Different Soil Types in Zaria

A. Bello, I. M. Hussaini

Microbiology Research Journal International, Page 1-6
DOI: 10.9734/MRJI/2017/30397

Aims: To isolate and characterize Bacillus thuringiensis from different soil types within Zaria and screen them for the possession of cry genes.

Methodology: Soil samples were collected from different sites in Zaria. A total of twelve Bacillus thuringiensis strains were isolated from the different soil types. This isolates screen for the possession of cry1, cry2, cry3 and cry4 genes using Polymerase Chain Reaction.

Results: Eight of the 12 isolates showed the presence of at least one cry gene, while the remaining four showed none. Cry1 was the most frequently detected gene (58.88%), followed by cry2 (16.67%), while cry3 and cry4 had the least occurrence (8.33%). Isolate L3 had cry1 and cry2, L2 had cry1 and cry3 while isolate L1 had cry2 and cry4.

Conclusion: Bacillus thuringiensis isolates from different soil types in Zaria harbor possess cry genes and as such are potential biocontrol agents. The presence of multiple cry gene in one isolate is of entomological importance as it could have broad spectrum of toxicity against different pests.

Open Access Original Research Article

Landfill Waste Effluents Increase the Population and Diversity of Soil Microorganisms: The Case of Olusosun Landfill, Lagos, Nigeria

Eucharia Ezenwanyi Nmema, Eunice Ngozi Anaele, Olakunle David Teniola

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/32420

Aims: This study investigated the impact of landfill waste effluents on the population and diversity of soil microorganisms, and a comparative study between landfill soil and effluent-free field soil.

Study Design: A comparative, investigative survey.

Place and Duration of Study: Biotechnology Laboratory, Federal Institute of Industrial Research, Oshodi, Lagos, between August 2015 and February 2016.  

Methodology: Soil samples were collected from the surface layers (1-20 cm) of alfisol at the landfill and a field located about 1000 meters from the landfill site. Isolation and characterization of bacteria, actinomycetes and fungi, physical and chemical analysis of the soil samples were performed. One-way analysis of variance (ANOVA) was used for statistical analysis, with level of significance at 0.05.

Results: Mean microbial counts (CFU g-1 dry soil) in landfill soil (Lfs) and field soil (Fs) respectively were: Total bacterial counts 87 ×105 and 72 ×105, coliforms 51×105 and 38 ×105, actinomycetes 44 ×105 and 22 ×105, and fungi 21×105 and 15 ×105, Lfs counts exceeding Fs counts significantly  (P < 0.05). The isolates included Proteobacteria (Lfs =16 spp.; Fs=7 spp.), Firmicutes (Lfs =20 spp.; Fs=10 spp.), Actinobacteria (Lfs =10 spp.; Fs=5 spp.), and Fungi (Lfs =15 spp.; Fs=13 spp.), Lfs yielding significantly higher diversity than Fs (P < 0.05). Lfs and Fs respectively contained: moisture (56.8 and 50.9%); pH (6.19 and 6.80); nitrogen (0.99 and 0.42%); phosphorus (553.4 and 371.8 mg/kg); Organic carbon (2.65 and 3.52%); cation exchange capacity (48.14 and 38.8 Cmmol/kg); sand (48.8 and 31.2%); clay (28.8 and 26.0%); silt (22.4 and 57.2%), highlighting differences in chemical and physical properties which support a greater diversity and population of microbes in Lfs more than Fs.

Conclusion: Effluents from landfills enhance the physical and chemical properties of soil, resulting in larger CFU, and greater diversity of all microorganisms. The greater diversity of microbes can be exploited for industry, medicine, agriculture, bioremediation, bio-control and research. The results reveal the importance of citing landfills far from farms, water bodies and residential areas to avoid health hazards in humans, livestock, and adverse effects on plants.

Open Access Original Research Article

Anticandidal Effect of Extracts of Wild Polypore, Trametes elegans, on Candida Species Isolated from Pregnant Women in Selected Hospitals in Southwest Nigeria

A. T. Adeyelu, V. O. Oyetayo, T. A. Onile, S. I. Awala

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/32914

Aim: Considering the significance of candidiasis among pregnant women, the study was designed to investigate the anticandidal effect of extracts of Trametes elegans (Spreng: Fr.) Fr. (fam.: Polyporaceae) against Candida species isolated from pregnant women and to screen for the phytochemical constituents of the crude extract of T. elegans.

Place and Duration of Study: Candida species were isolated from 132 high vaginal swabs (HVS) collected from pregnant women attending ten selected hospitals in Ondo, Osun and Oyo States, Nigeria.

Methods: Extracts of Trametes elegans was prepared with methanol, acetone and n-hexane. Phytochemical screening of the macrofungus extracts were thereafter performed qualitatively and quantitatively. The isolated Candida species were subjected to antifungal assay to determine the anticandidal efficacy of the macrofungus extracts.

Results: A total of 67 Candida isolates were obtained from the patients. The prevalent organisms were C. albicans (49/67, 73.13%), C. glabrata (9/67, 13.43%), C. krusei (6/67, 8.96%) and C. tropicalis (3/67, 4.48%). Methanol gave the highest yield (3.4 mg/g), while n-hexane gave the least (0.7 mg/g). All the extracts contained saponin, tannin, steroid, terpenoid and cardiac glycosides, while flavonoid was only found in acetone extracts. Saponin was highest (31.77 mg/g) while flavonoid content was least (1.65 mg/g). Zones of inhibition ranging from 5.00 to 30.00 mm, 4.00 to 15.67 mm and 4.33 to 17.67 mm were produced by methanol, acetone and n-hexane extracts respectively. Methanol extract of T. elegans produced the highest anticandidal activity with an inhibition zone of 30.00 mm against isolate A3 (C. albicans.) The least inhibition zone (4.00 mm) was recorded with acetone extract of T. elegans against isolate A2.

Conclusion: The high anticandidal activity exhibited by mushroom extracts suggests that bioactive compounds from these mushrooms could be developed into antifungal agents for the treatment of candidiasis.

Open Access Original Research Article

Antimicrobial Resistance of Klebsiella pneumoniae -ESBL Producing Strains Isolated from Clinical Specimens in Abidjan (Cote de Ivoire)

Joel Eric Tahou, Nathalie Kouadio Guessennd, Paulin Didier Sokouri, Valérie Gbonon, Fernique Konan, Jules Kouadio, Karine Kossia Gba, Baguy Mohamed Ouattara, Simon-Pierre Assanvo N’guetta

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/MRJI/2017/34085

Aims: The objective of this study is to detect the prevalence of qnr genes in broad-spectrum beta-lactamase producing Klebsiella pneumoniae, involved in hospital and community-acquired infections.

Study Design: It is a retrospective study.

Place and Duration of Study: Bacteriology and virology laboratorie of Institut Pasteur, Abidjan, Côte d'Ivoire.

Methodology: From January 2011 to June 2016, 350 Klebsiella pneumoniae were isolated from various clinical specimens and identified by conventional bacteriological tests. Antibiotic resistance (beta-lactams, quinolones and aminoglycosides) and detection of broad-spectrum beta-lactamases were assessed by the diffusion method and the synergy test, respectively. Molecular characterization of quinolone resistance genes (qnr A, qnr B and qnr S) was performed by the conventional polymerase chain reaction (PCR).

Results: Of the 350 Klebsiella pneumoniae isolates, 91(26%) were detected as ESBL producer, 36.2% (n=33) recovered from urine, 24.2% (n=22) from pus and 20.8% (n=19) from blood culture respectively. 46(33%) strains were idenifed to carry qnr genes, qnrB predominate 33(71%), followed by qnr 12(26.1%) and qnrA 1(2.2%). The strains exhibited high resistance to most of the agents tested, expect imipemen, low resistance to amikacin 4.1%, moderate to cefoxitin 31.8% and 54.9% with amoxicillin-clauvanic acid.

Conclusion: Although these observed prevalences are small proportions, this can be seen as a warning signal for the future. The emergence and dissemination of resistance genes in Côte d'Ivoire could pose a public health problem. Thus, the establishment of a relevant resistance surveillance policy to better control the circulation of multidrug-resistant strains is necessary.

Open Access Original Research Article

Antibacterial, Antioxidant Activity and Phytochemical Analysis of Euphorbia hirta Linn.

Savita Jakhar, Pushpa Dahiya

Microbiology Research Journal International, Page 1-12
DOI: 10.9734/MRJI/2017/34446

Objective: Crude extracts were prepared from aerial parts of Euphorbia hirta Linn. in four solvents i.e. water, acetone, ethanol and petroleum ether. Extracts were investigated for their phytochemical, antibacterial and antioxidant properties.

Methods: Plant extracts were prepared by using Soxhlet apparatus. Antibacterial potential was assessed by disc diffusion method against six bacterial strains viz. Klebsiella pneumoniae (MTCC NO 109), Staphylococcus aureus (MTCC NO 96), Pseudomonas aeruginosa (MTCC NO 2453), Mycobacterium smegmatis (MTCC NO 992), Bacillus subtilis (MTCC NO 2057) and Chromobacterium violaceum (MTCC NO 2656). Minimum inhibitory concentration was determined by microbroth dilution method, only to those bacterial strains which showed a significant zone of inhibition by disc diffusion method. The extracts were also examined for the presence of various phytoconstituents, total phenolic and flavonoid content using standard methods. Free radical scavenging activity was assessed by DPPH method.

Results: The plant extracts showed a wide spectrum of inhibition against the test pathogens thus justifying the use of plant in traditional medicine. Acetone, aqueous and ethanol extracts exhibited stronger antibacterial activity as compared to the petroleum ether extract. The maximum activity recorded was 17.6±0.57 mm with 200 mg/ml concentration of ethanol extract against Klebsiella pneumoniae. Petroleum ether extract was found to be least effective as it showed zone of inhibition only against Chromobacterium violaceum. Aqueous extract of the plant showed highest antioxidant activity and minimum IC50 value (105.39 µg/ml) followed by acetone (371.0 µg/ml), ethanol (504.92 µg/ml) and petroleum ether (645.12 µg/ml) extracts. Aqueous extract showed highest TPC value (8.2 mgGAE/g), followed by acetone (6.4 mgGAE/g) and ethanol (5.84 mgGAE/g). Similarly, highest TFC value (4.6 mgQE/g) was also observed against aqueous extract, followed by acetone (2.05 mgQE/g) and ethanol extract (1.82 mgQE/g). Petroleum ether extract exhibited minimum TFC value i.e. 0.79 mgQE/g.

Conclusions: The present in vitro study revealed that E. hirta is a rich source of bioactive compounds with significant antibacterial and antioxidant activity. However, further investigation with ethno-pharmacological approach is needed for better understanding of its utility in health care.