Open Access Original Research Article

Evaluation of Microbial Availability and Linkages to the Physicochemical Quality of Natural and Deteriorated Rubber Latexes

Augusta O. Mmuoegbulam, Celestina C. Ugwu, Ignatius F. Obi, Emmanuel E. Igwe

Microbiology Research Journal International, Page 1-9
DOI: 10.9734/MRJI/2017/36435

Natural and deteriorated rubber latex samples were analyzed for bacteriological and physicochemical quality. Bacterial isolates obtained after 24 hours of incubation ranged from 1.5x106 to 1.58x108 CFU/mL, corresponding to three weeks-deteriorated and natural rubber  latexes respectively. However, after 48 hours of incubation, the bacterial counts in the natural rubber latex, one week deteriorated rubber, two weeks deteriorated and three weeks deteriorated rubbers were 1.7x108 CFU/mL, 1.094x108 CFU/mL, and 7.1x107 CFU/mL respectively. Heterotrophic fungal counts ranged from 3.2x107 to 7.8x107 CFU/mL corresponding to three weeks-deteriorated and natural rubber latexes respectively. Statistical analysis for bacterial and fungal isolates showed that there was no significant difference in the mean bacterial and fungal counts within the samples at 95% confidence interval. Microorganisms isolated from natural and deteriorated rubber samples include Acetobacter spp., Enterococcus spp., Aspergillus spp., Actinomyces spp., Penicillium spp., Saccharomyces spp.  Physicochemical analysis showed a weakly acidic condition of natural rubber latex and an extreme degree of hardness in all the deteriorated rubber samples.

Open Access Original Research Article

Antibacterial Activity of Actinomycetes Isolated from Waste Dump Soil from Western Uganda

Adamu Almustapha Aliero, Eilu Emmanue, Maniga Nyabayo Josephat, Sambo Haruna Aliyu, Matilda Angela Okech, John Odda

Microbiology Research Journal International, Page 1-14
DOI: 10.9734/MRJI/2017/36459

Aims: To determine the antibacterial activity of actinomycetes isolated from waste dump soil in Western Uganda.

Study Design:  The study was an experimental laboratory design.

Place and Duration of Study: Waste dump soil samples were collected from Bushenyi, Kabale, Kasese, and Mbarara districts  in Western Uganda, from May, 2016 to February, 2017.

Methodology: Actinomycetes were isolated from 22 waste dump soil samples collected using standard spread plate technique, all isolates were screened primarily using cross streak method against Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, and Staphylococcus aureus ATCC25923, resistant clinical bacteria: Escherichia coli 2966, Pseudomonas aeruginosa 2929, and Staphylococcus aureus 2876 (MRSA). Secondary screening was carried out by first growing all fifty six isolates (56) in broth media and their supernatants were tested for activity using agar well diffusion method. The remaining broths were extracted using ethanol. The ethanol extract was also tested for antibacterial activity using agar well diffusion method. The MIC was determined using tubes dilution technique and MBC was determined by culture method.

Results: Fifty six (56) actinomycetes isolates were isolated from 22 waste dump soil samples. Four (7.14%) isolates showed activity to at least one test bacteria during primary screening.  Eight (14.29%) actinomycetes isolates fermented broth showed activity to at least one test bacteria during secondary screening, with mean zone of inhibition of 7.67±1.45 to 33.67±2.03 mm. Isolate KBMWDSb6 showed activity to all test bacteria with exception of resistant Staphylococcus aureus 2876 (MRSA) while isolates BRWDSc (SP) and KBRWDSa3 (RF) showed activity to all sensitive standard isolates and resistant Staphylococcus aureus 2876 (MRSA). Eleven (19.64%) actinomycets isolates ethanol extracts showed activity to at least one test bacteria with mean zone of inhibition 7.33±1.20 to 31.67±1.45 mm. The MIC and MBC of the extracts were found to be 0.07 to 0.62mg/mL and 0.15 to 1.25mg/mL respectively.

Conclusion: The findings of this study indicated that actinomycetes spp isolated from waste dump soil collected from Western Uganda have ability to produce bioactive compounds with activity against bacteria including clinically drugs resistant bacterial isolates. This could be a good source of novel antibiotics.

Open Access Original Research Article

Profiling Rhizosphere Microbes on the Root of Maize (Zea mays) Planted in an Alfisol for Selection as Plant Growth Promoting Rhizobacteria (PGPR)

L. B. Taiwo, B. V. Ailenokhuoria, A. O. Oyedele

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/36404

Maize (Zea mays L. Merill) root rhizosphere, being a metabolite-enriched niche was profiled with the objective of isolating Plant Growth Promoting Rhizobacteria (PGPR) for bio-fertilizer production. Isolation was carried out from the root surface and rhizosphere soil samples of the plant using standard procedures. Cultural, physiological and biochemical procedures were used to identify the isolates. Eighty (80) isolates obtained were screened for growth promoting attributes and sixteen (16) representative isolates selected, and further identified using molecular methods by sequencing of their 16S rDNA gene. Sixty three percent of the characterized organisms exhibited sequence homology level equal or greater than 90% with those of the gene bank. Microorganisms with pathogenic characteristics were eliminated. As a result of this, Bacillus thuringiensis, Pseudomonas putida and Klebsiella varricola selected, were further screened in vitro for Indole acetic acid (IAA), Gibberellic acid (GA) and Cytokinin production using standard assay methods.  Klebsiella varricola produced 19.697 mg/L of GA, 0.348 mg/L of IAA and 1.804 mg/L of Cytokinin. Pseudomonas putida had 2.693 mg/L of GA, 0.152 mg/L and of IAA and 5.066 mg/L of Cytokinin in solution while Bacillus thuringiensis excreted 15.091 mg/L, 0.132 mg/L and 2.410 mg/L of GA, IAA and Cytokinin respectively. The 3 PGPR are considered suitable for biofertilization programme.

Open Access Original Research Article

Degradative Studies of Crude-Oil Degrading Bacteria Isolated from Hydrocarbon Polluted Surface Water in Agbabu, Ondo State

T. O. Olowomofe, J. O. Oluyege, P. W. Gbaraneh, Olufunke Afolayan

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/35362

Hydrocarbon-utilizing potentials of bacteria isolated from twelve different bitumen-contaminated sites in Agbabu, Ondo State were investigated. Water samples were collected and analyzed using standard microbiological techniques. The mean total bacterial count and mean total hydrocarbon- degrading bacterial counts were determined using pour plate technique. The hydrocarbon-utilizing potentials of the isolates were further determined by screening them in mineral salt broth supplemented with 2% crude-oil over a period of 10 days. The growth of the isolates was monitored by measuring the absorbance (OD600nm) and Total viable count (log10 CFU/ml). Five isolates selected based on their ability to utilize crude-oil were subjected to conventional biosurfactant screening tests: qualitatively (drop collapse) and quantitatively (oil spreading and emulsification activity). The selected five isolates were used to degrade crude-oil and percentage degradation was determined by Gas chromatography analysis. The isolates were identified by the amplification and sequencing of the 16S rRNA sequences. The Mean Total bacteria count and the Mean Total hydrocarbon-utilizing bacteria count were 7.70 (log10 CFU/ml) and 7.14 (log10 CFU/ml) respectively. Out of the isolates screened for biosurfactant production, only Pseudomonas and Bacillus species were positive for all the tests. They had a clear zone of 4 mm each and an emulsification capacity of 65.50% and 57.13% respectively. The percentage degradation of crude oil by Pseudomonas aeruginosa, Micrococcus luteus, Bacillus cereus, Acaligens faecalis and B. lichenformis were 78.67%, 68.27% 63.16%, 54.28% and 51.54% respectively. Pseudomonas aeruginosa had the highest % degradation (78.67%) while the lowest % degradation (51.54%) was observed by B. lichenformis. The identities of the isolates revealed by 16S rRNA sequences were Pseudomonas aeruginosaBacillus cereus, B. lichenformis Acaligens faecalis and Micrococcus luteus.

Open Access Original Research Article

Plasmid Carriage and Antibiotics Susceptibility of Cultivable Bacteria Isolated from Hospital Wastewater

M. P. Uko, S. C. U. Nwachukwu, S. I. Umana

Microbiology Research Journal International, Page 1-9
DOI: 10.9734/MRJI/2017/36417

Careless discharge of wastewater is another source of which the environmental health is continuously being threatened. Hospital wastewater contains clinically relevant strains. Study was undertaken on the prevalence of antibiotics resistant bacteria (ARB) in hospital wastewater and to determine the presence of plasmid and its association with antibiotic resistance expression among the bacteria using standard microbiological techniques and alkaline lysis method, respectively. Antibiotic susceptibility was determined by use of the disk diffusion method. Total heterotrophic count of 1.36 x 107 and 2.0 x 106 CFU/mL were obtained, Escherichia coli count gave 2.1 x 105 and 1.6 x 10CFU/mL and Staphylococcal count gave 1.4 x 10and 1.2 x 105 CFU/mL. Species of Staphylococcus, Pseudomonas, Klebsiella, Bacillus, Escherichia, Acinetobacter and Salmonella, were identified. Based on a differential staining process, the bacteria were tested against some commonly used antibiotics. A high profile of multi-antibiotics resistance was displayed among the bacteria. The percentage of resistance to the antibiotics were COT - 15%, AUG - 15%, GEN - 11%, TET - 10%, OFL - 3%, AMX - 10%, NIT - 5%, NAL - 6%, CXC - 10%, CHL - 6%, ERY - 3% and STR - 6%. Approximately 58% of the bacteria carried plasmids. Plasmid band size of 23.1 kbp was common among the bacteria. Resistance was observed in bacteria with plasmids as well as in those without plasmids. On curing, the organisms showed reduced resistance to the antibiotics while Pseudomonas aeruginosa and Bacillus sp. maintained their resistant pattern. Hospital wastewater contains loads of antibiotic resistant bacteria whose resistance in part are carried in plasmid. It contributes to environmental contamination with clinically important strains of microorganisms. The practice of releasing hospital wastewater into the environments should be strongly monitored and prohibited as the environment has a lot to do in our functioning and metabolic efficiency and therefore should be kept clean.