South Asian Journal of Research in Microbiology

A study on the antibacterial activities of Bryophylum pinnatum against multidrug resistant bacterial pathogens was carried out in this research. Air-dried and powered Bryophylum pinnatum leaves was extracted using ethanol and aqueous solvents. Five bacteria strains including Staphylococcus aureus, Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa were obtained from the University of Benin Teaching Hospital and they were preliminarily identified using standard microbiological methods. Antibacterial activity was carried out using agar well diffusion method. Mean zone diameter of inhibition in aqueous extract ranged from 9.20±0.17-10.50±0.50mm and 9.30±0.33- 10.33±0.89mm against Escherichia coli and Staphylococcus aureus respectively at 25-100mg/ml. In the ethanol extract, mean zone of inhibition ranged from 9.50±0.28-13.33±0.88mm and 10.67±0.67-19.00±0.58mm at concentration range of 6.25-100mg/ml.  Minimum inhibitory concentrations of ethanol extract ranged from 6.25-100 mg/ml against bacterial strains. While those of aqueous extract ranged from 25-100 mg/ml against bacterial isolates. Minimum bactericidal/fungicidal concentrations of ethanol extract ranged from 25-50 mg/ml. While in the aqueous extract, value was 50 mg/ml and against bacteria. The test bacterial pathogens were found to possess multiple drug resistance potential with multidrug resistance index ranging from 0.3 – 0.5. This study has shown that multidrug resistant clinical bacterial pathogens are sensitive to aqueous extract of Bryophyllum pinatum.

Solanum tubersum is the fourth most challenging plant in Egypt, affected by several fungi, viral and bacterial diseases. Bacterial and fungal isolates (Brown rot disease (Ralstonia solaniserum), soft root disease (Pectobacterium carotovora) and dry rot disease (Fusarium oxisporum) were collected. The green extracts of silver nanoparticles were prepared by means of aqueous extracts of three wild plants, Physalis peruviana (leaves, red and green fruits) (N1, N2 and N3), Solanum nigrum (fruit) (N4) and Moringa oliefera (leaves) (N5). SEM, TEM, FT-IR and X-RD obtained the characterization of the biosynthesis of silver nanoparticles. The results indicated that nanoparticles were spherical, smooth and the sizes varied between 12 and 33 nm. The activity of the nanoparticle formulations was tested against the bacterial isolates using agar diffusion method and one fungus using mycelial growth method. The results also elucidated that N5 formulation showed a significantly potent antibacterial activity against R. solanacearum. However, N1 formulation was the highest active one against P. carotovra. In addition, the antifungal activity indicated that N1 had the highest effect (EC₅₀ = 687.03 mg/L) followed by N3 (EC₅₀ = 981.61 mg/L) against F. oxysporium. Nanoparticles synthesized by wild plants could be used as safe alternatives to harmful microbicides.

Aim: To determine microbiological quality of fresh water in Isiokpo community.

Study Design: This study employs standard scientific methods, statistical analysis and interpretation.

Place and duration of the Study: Fresh water samples were collected from Isiokpo community in Ikwerre L.G.A. of Rivers State, Nigeria. Sampling was done every two weeks from three stations of Isiokpo river for duration of six months (February–July, 2018). Samples were transported in ice packed coolers to the Microbiology Laboratory of Rivers State University, Port Harcourt, and immediately processed for analysis. 

Methodology: Ten- fold serial dilution technique was adopted after which 0.1 ml of appropriately diluted stock was inoculated onto sterile Microbiological media. Spread plate technique was employed for the isolation, enumeration and identification of microorganisms. The APHA standards were adopted in the determination of physico-chemical parameters which include turbidity, colour, odour, pH, conductivity, total suspended solids, total dissolved solids, nitrate, sulphate, calcium and BOD₅. The  Duncan  multiple range test  was  employed  for analysis  of  variance  (ANOVA) of  the  data  obtained.

Results: The mean counts for Total heterotrophic bacterial counts ranged from 4.77±0.20 log₁₀ CFU/ml to 4.92±0.11 log₁₀ CFU/ml. Total coliform  bacteria  ranged  from  4.28±0.25 to 4.60±0.25log₁₀ CFU/ml. Total Vibrio counts  ranged from 1.77±1.97 log₁₀ CFU/ml to 4.25±0.09 log₁₀ CFU/ml. Total Pseudomonas  counts ranged  from  2.48±1.93 log₁₀ CFU/ml  to 4.0217±0.34 log₁₀ CFU/ml. Total  heterotrophic fungal counts ranged from  2.31±1.81 log₁₀ CFU/ml  to 4.21± 0.22 log₁₀ CFU/ml in all the stations. The microorganisms isolated belong to the genera of Bacillus, Escherichia, Klebsiella, Pseudomonas, Staphylococcus, Shigella, Vibrio, Aspergillus, Penicillium, Mucor and Rhizopus. The pH values ranged from 5.60 to 6.80, Conductivity 35 to 40 µs/cm, Total suspended solids (TSS) 48 mg/L to 54.00 mg/L, Total Dissolved Solids 5.20 to 6.50 mg/L, Nitrate 1.00 to 1.45 mg/L, Sulphate 1.00 to 1.30 mg/L, Calcium 6.00 to 9.20 mg/L and BOD 5.30 to               6.20 mg/L in all the stations.

Conclusion: The presence of E. coli which is an indicator of fecal contamination is enough to suspect that the water body is contaminated with fecal matter and pathogenic bacteria. The water should therefore not be put to human use without proper treatment because the water is of low quality and constitute a danger to public health.

Aim: This study aimed at evaluating the microbial quality and proximate composition of pita samples from Akure metropolis.

Place and Duration of Study: Microbiology and Industrial Chemistry laboratories of the Federal University of Technology, Akure (FUTA), Ondo State, Nigeria, between January 2016 and June 2016.

Methodology: Pita samples were evaluated using standard microbiological techniques to ascertain microbial load and types after purchase from vendors utilizing them alone or in production of other foods. Antibiotic susceptibility profile of isolates was also determined. Proximate composition analysis of samples was also performed.

Results: Average bacterial count was 1.0±0.9 cfu/g, while average fungal count was 2.0±1.2 sfu/g. The fungi isolated were Rhizopus stolonifer, Saccharomyces cerevisiae and Aspergillus niger; while the bacteria isolated were Bacillus cereus, Staphylococcus sp., Micrococcus luteus, Pseudomonas aeruginosa, and Proteus vulgaris. Microbial zones of inhibition ranged from 17 mm to 23.50 mm. Micrococcus luteus, Staphylococcus aureus and Pseudomonas aeruginosa were most susceptible to gentamycin, pefloxacin and amoxycillin, respectively. Staphylococcus aureus showed the widest antimicrobial resistant pattern. The highest carbohydrate content was recorded as 78.99 %, while bread samples showed low ash content (0.65 %).

Conclusion: Pita bread is not a common staple compared to leavened breads but provides appreciable level of nutrients. Pita bread requires regular microbial assessment to determine their safety for direct consumption or use in production of other food products.

Fifty-eight fungal isolates were isolated from salt soil, whey and salt fish on medium supplemented with 0.5% NaCl. Out of 58 isolates, 49 were capable to grow on medium supplemented with 1 % NaCl. These halo-tolerant isolates were tested to produce plant growth regulators (PGR) on solid or in broth medium. On solid medium, 9 halo-tolerant isolates out of 58 isolates were gave indole acetic acid (IAA) which appeared red zone around growth zone with index ranged from 0.25 to 0.56. While in broth medium, 9 isolates were tried to produce IAA and gibberellic acid (GA) in presence of NaCl at 0.5 or 1%. The maximum IAA and GA production were obtained by FS12 isolate (4.32 and 4.52 mg/100ml) and by FW2 isolate (2.71 and 2.92 mg/100ml) at 0.5% and 1% NaCl, respectively. FS12 was selected as the most efficient isolate for plant growth regulators (PGR) production and identified as Aspergillus niger. Carbon and nitrogen sources were studied
for PGR optimization by the tested strain. Whey and peptone were used as a sole carbon and nitrogen source, where increased the IAA and GA production about 15.4% and 71.3% as compared to control (basal medium).