Open Access Original Research Article

Antagonistic Potential of Soil Bacteria against Plant Pathogenic Fungi: Aspergillus niger

A. P. Rao, P. T. Nnaji

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/MRJI/2017/29725

Aims: This study was carried out with the aim of assessing the antagonistic potentials of soil bacteria against the plant pathogenic fungi Aspergillus niger.

Study Design: The complete Randomized Design was the experimental design for this study.

Place and duration of study:  This study took place in University of Calabar, Cross River State Nigeria within the pace of one month.

Methodology: Standard microbiological methods were used to identify bacteria and obtain pure culture of fungi

Result: Bacterial isolates were evaluated for their potential of antagonism against Aspergillus niger isolated from spoilt tomatoes. The percentage inhibition of mycelia growth by these isolates recorded values as 27%, 0%, 66%, 40%, 97%, 0% and 23% respectively. The isolates were analyzed and identified as Bacillus spp, Enterobacter spp., Pseudomonas spp., Proteus spp., Escherichia coliStreptococcus spp. and Staphylococcus spp respectively.

Conclusion: In the present work high levels of in vitro control of A. niger have been verified by E. coliisolates. However, in future investigations molecular studies should be carried out confirming that the isolates obtained from E. coli are not pathogenic to humans.

Open Access Original Research Article

Gram Negative Bacterial Diversity and Antimicrobial Resistance Profiles in Heavily Polluted Environmental Samples around The Sır Dam Lake (Turkey)

Emel B. Buyukunal, Sevcihan Tas

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/32773

Background: The Sır Dam Lake is located on the Ceyhan River and provides a major water-supply to agricultural fields in Southern Turkey. However, it has so far received various industrial and household wastes in excessive amounts.

Aims: This study aims to analyze Gram negative bacterial diversity and antimicrobial resistance profiles in polluted environmental samples (soil, sludge, water) collected around the Dam Lake.

Study Design: Gram negative bacteria were isolated from 15 polluted environmental samples and identified using both phenotypic and molecular methods. In addition, antimicrobial resistance profiles of the strains were determined by disk diffusion method.

Place and Duration of Study: Environmental samples were collected from 15 different locations in Avsar region located around the Sır Dam Lake in March 2014.

Methodology: Gram negative bacterial strains were identified based on biochemical tests. Biochemical identification of the bacterial isolates was further verified using CHROMagar ECC (France). A fragment corresponding to 16S rRNA gene was amplified using universal primers. The sequence analyses of amplified fragments were used for molecular identification of unidentified isolates by biochemical tests. Antimicrobial susceptibilities of the isolates were determined with disk diffusion method.

Results: A total of 17 identified strains were grouped as Escherichia coli (n=8), non-fermenters (n=5) and Enterobacteriaceae (n=4). Only two strains (Klebsiella oxytoca and Enterobacter spp.) were identified from EnterobacteriaceaeAcidovorax temperans emerged as the second predominant bacteria following to E. coli and did not display significant resistance to the tested antimicrobials. However, most of E. coli isolates as well as a single K. oxytoca and a single Acinetobacter spp. isolates displayed higher multiple antimicrobial resistance (MAR) index values that should be considered seriously for local public health.

Conclusion: Gram negative bacterial distribution remarked the presence of fecal contamination. In addition, the presence of A. temperans might indicate a presence of different types of pollution, and this organism might be useful in biodegradation processes after its metabolic capability is defined.

Open Access Original Research Article

Chemical Constituents Analysis of Petroleum Ether Extract from Xylaria striata by GC-MS

Luo Jing, Yang Wei, Wu Jiaoqi, Ren Qingyuan, He Xinsheng, Huang Yi

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/MRJI/2017/32719

Aims: To analyze the chemical constituents of petroleum ether extract of Xylaria striata.

Methodology: Xylaria striata was extracted by petroleum ether, and then the extract was analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). Identification of compounds was achieved from their GC retention indices (RI) relative to n-alkanes and by computer search using libraries of NIST05, as well as comparisons of the fragmentation pattern of the mass spectra with data published in the literature.

Results: Thirty-seven compounds were separated by gas chromatography. Based on the NIST spectral library and corresponding literature information, thirty compounds which covered 98.43% of the total peaks were identified. Most of them were fatty acids and their esters (77.58%), steroids (19.44%). The methyl linoleate covered 38.23% of the total peaks, while methyl palmitate was 19.12%, methyl linoleate (9-cis, 12-trans) was 5.15%, methyl oleate was 4.43% and methyl stearate was 3.3%.

Conclusion: This is the first report of chemical constituents of the petroleum ether extract of Xylaria striataby GC-MS. The result will provide ample information for further exploration and utilization of Xylaria striata.

Open Access Short Research Article

Antimicrobial Potential of Dacryodes edulis against Selected Clinical Bacterial Isolates

A. F. Amise, J. A. Lennox, B. E. Agbo

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/MRJI/2017/29447

The antimicrobial potential of Dacryodes edulis was investigated to determine the antimicrobial properties of the collected raw D. edulis pulp and seed extracts on some medically important human pathogens. The research was investigated against the selected human pathogens using standard microbiological and biochemical procedures. The D. edulis samples were harvested aseptically between the periods of April to June 2016 from its tree located at IBB way, Calabar Municipality, Nigeria. The aqueous and ethanolic extracts of the seed and pulp at varying concentrations of 1 g/10 ml, 2 g/10 ml, 4 g/10 ml, 5 g/10 ml  was tested against some selected human pathogens such as Staphylococcus aureus, Klebsiella pneumonia, Enterococcus faecalis, Escherichia coli,  Pseudomonas aeruginosa and  Proteus vulgaris. The antimicrobial susceptibility results of the ethanol extracts of D. edulis seed showed marginally higher zones of inhibition to the clinical bacterial isolates tested than the ethanol extract of the pulp tested against the same clinical isolates. The organisms were resistant to the aqueous extracts of both the pulp and seed. The seed ethanol extracts showed a higher zone of inhibition of 21 mm against K. pneumoniae and 18 mm against P. vulgarisas compared to 18 mm as against K. pneumoniae and 17 mm against P. vulgaris showed by Gentamycin used as standard antibiotic control. The result of these has shown that D. edulis could be of immense importance in our nation’s young pharmaceutical industry for the development of new chemotherapeutic agent to address unmet therapeutic needs.

Open Access Short Research Article

Bacterial and Fungal Contaminants in Mycobacterium tuberculosis Cultures at National Tuberculosis Referral Laboratory-Kampala

Tushabe John Vianney, Katuura Esther, Iramiot J. Stanley

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/MRJI/2017/32801

Aim: This study was aimed at identification of fungal and bacterial contaminants in Tuberculosis cultures at the Uganda National Reference Laboratory (NTRL).

Methods: The cultures were previously grown on Lowenstein-Jensen (LJ) medium in bottle slants. The method used involved conventional culture methods and biochemical characterization of the contaminants. Bacterial cultures were carried out in both aerobic and carbon dioxide incubators where required and to the respective temperatures of the organisms. Growth was observed between 24-48 hours for bacterial and up to 72 hours for yeast contaminants. Cultures on SDA were also monitored for three weeks for possible growth of filamentous fungi.

Results: The identified bacteria mostly included; S. pyogenes, S. aureus, E. coli, P. aeruginosa, K. pneumoniae, and least isolated were; S. marcescens, H. influenza, S. pneumoniae and B. subtilis Fungal contaminants were A. fumigatus and C. albicans.

Conclusion: Based on this study a relatively increased level of contamination was noted. We recommend that high level of aseptic techniques be maintained in addition to the current standards in order to reduce the level of bacterial and fungal contaminants in TB cultures so as to improve the detection rate of Mycobacteria tuberculosis by culture method.