South Asian Journal of Research in Microbiology

Aim: To assess the bioremediation potential of Pseudomonas aeruginosa and Bacillus megaterium on oil spill dispersant polluted terrestrial soil.

Study Design: The study employs experimental design, statistical analysis of data and interpretation.

Place and Duration of the Study: Polluted Terrestrial Soil (Ts) samples were collected from Kegbara-Dere community in Gokana Local Government Area of Rivers State with sterile shovel from three different spots at the same location and put in black polythene bags and transported to the microbiological laboratory within 24 hours for physicochemical and microbiological analyses. Oil spill dispersant (OSD/LT and OSD/Seacare) were obtained from Baker and Hughes Nigeria Limited in Rivers state, Nigeria.

Methodology: Standard microbiological procedures were used to enumerate, isolate and identify the bacterial isolates. Pseudomonas aeruginosa and Bacillus megaterium in oil spill dispersants contaminated soil were monitored over a period of 1, 7, 14, 21 and 28 days respectively for their bioremediation potentials.

Results: The presence of Pseudomonas aeruginosa (Pa) or Bacillus megaterium(Bm) in oil spill dispersant polluted soils enhanced decrease in Total Hydrocarbon Content (THC) of the soil. THC for control soil reduced from 18348.68 mg/kg to 9111.84 mg/kg; TS+OSD/LT+Bm, 18348.68 to 7092.11 mg/kg; TS+OSD/LT+Pa, 18348.68 to 6263.16(mg/kg); TS+OSD/LT+Bm+Pa, 18348.68 to 2473.68 mg/kg; TS+OSD/SC+Bm, 18348.68 to 6421.05 mg/kg; TS+OSD/SC+Pa, 18348.68 to 5618.42 mg/kg; TS+OSD/SC+Bm+Pa, 18348.68 to 5835.53 mg/kg, between the first (day 1 ) and  last day ( day 28). The percentage (%) bioremediation rate of polluted soil was as follows: control (TS(CRTL) 50.3%, TS+OSD/LT+Bm 61.3%, OSD/LT+Pa 65.9%, and OSD/LT+Bm+Pa 86.5% Whereas, TS+OSD/Seacare+Bm had 65.0%, OSD/Seacare+Pa 69.4%, OSD/Seacare+Bm+Pa 68.2% respectively. The highest percentages of THC in this study were from soil samples treated with oil spill dispersant and organisms while the least was observed in treatments without oil spill dispersant and organism. This suggests that microorganisms are more abundant in oil spill dispersant polluted soils than unpolluted soils.

Conclusion: From this study, it was observed that bioremediation of dispersant polluted environments could be achieved by stimulation of native microorganisms such as Pseudomonas aeruginosa KX828570 and Bacillus megaterium KY085976 and this would be cost effective in the clean-up strategy for such pollutants.

In this study, hydrocarbon degradation potentials of heterotrophic bacteria isolated from oil-polluted soil were examined. Samples were collected from Sakpenwa, an oil producing community in Tai LGA of Rivers State, Nigeria and analyzed for physicochemical and microbiological properties using standard techniques. Hydrocarbon utilizing bacteria (HUB) were isolated by vapour phase transfer method using mineral salt medium. The biodegradation study was carried out on a standard laboratory shaker for 30 days in Bushnell -Haas agar supplemented with 5% of crude oil. Fifteen (15) bacterial isolates were screened for hydrocarbon degradation potentials of which five isolates exhibited high hydrocarbon degradability.  The following parameters were monitored using each of the five isolates and a consortium during the biodegradation study: Colour change, Optical density (OD), pH, Total Petroleum Hydrocarbon (TPH), Total Hydrocarbon Contents (THC) and Total Cuturable Heterotrophic Bacterial Counts (TCHBC). The mean TCHBC ranged from 1.65×107 to 2.27×108cfu/ml while the mean Total Culturable Hydrocarbon Utilizing Bacterial Counts ranged from 1.09×104 to 3.9×105. The optical density varied from 0.09±0.02 - 2.57±0.00 and pH ranged from 2.98±0.09 - 6.98±0.09. The optical density varied to .09±0.02 - 2.57±0.00 and pH ranged from 2.98±0.09 -0.98±0.09. The gravimetric analysis showed that Bacillus sp., Pseudomonas sp. Alcaligenes sp. and Acinetobacter sp. were able to degrade 96.90%, 99.60%, 99.20% and 99.70% of the hydrocarbons respectively. This study demonstrated that indigenous bacterial species were highly efficient in the biodegradation of petroleum hydrocarbons.

Aims: Nosocomial infection (NI) is one of the most important problems facing the world. This work is dedicated to investigating the prevalence rates of NI in addition to estimating the minimum inhibition concentration (MIC) of commercial antibiotics on isolated bacteria in order to determine the most diluted antibiotic that performed well with more efficiency and minimal toxicity.

Place and Duration of Study: Gastroenterology Surgical Center, Mansoura University, Mansoura, Egypt, between July 2017 and July 2018.

Methodology: This study included 368 different samples (urine, stool, sputum and surgical wounds) from 100 patients A total of 15 commercial antibiotics selected from seven families having different mode of action were used.

Results: Our findings demonstrated that the highest prevalence rate of NI was detected in K. pneumoniae (40%, n=56) followed by MRSA (22.85%, n=32), E. coli (20%, n=28), P. mirabilis (7.85%, n=11), P. putida (5%, n=7) and finally P. aeruginosa (4.3%, n=6). In addition, the results showed variable MICs of various antibiotics on isolated bacteria associated with NI.

Conclusion: Interestingly, our findings showed that quinolones family had the highest impact on all types of isolated bacteria associated with nosocomial infections.

Introduction: The presence of pesticides in soils could result in alterations in microbial activities (enzyme activities, microbial populations), soil physical and chemical properties.

Research gap/Challenges: Insufficient literatures on extensive monitoring of soil quality through enzyme activity, during pesticides application. Existing literatures concerning analysis of effect of pesticide application on soil enzyme activity are not comprehensive with respect to number of soil enzymes analysed.

Aim/Objective: The study was conducted to investigate the effect of carbofuran and paraquat on soil biochemical characteristics on certain soils in the Niger Delta region of Nigeria.

Methodology: These pesticides were applied at recommended doses, their effects on soil organic carbon, enzymes activity and microbial populations were assessed using standard methods. The enzymes monitored were amylase, invertase, protease, urease, phosphatase and dehydrogenase. Microbial counts were carried out for total heterotrophic bacteria, fungi, actinomycetes, nitrifying bacteria and phosphate solubilizers using the spread plate method.

Results: There were variations in the different enzyme activities in carbofuran – and paraquat - treated soil during this research. Dehydrogenase activity increased in treated soils. Also, urease activity was lower compared to other enzyme activities. As the study progressed, variations in values of soil organic carbon were observed.  There was a gradual increase in microbial counts and can be traceable to their ability to temporarily mineralize and use the pesticides as carbon and energy source. The soil organic carbon, enzymes and microbial counts values were significantly different at P=0.05.

Conclusion: This research revealed that the pesticides cause temporal impact on microbial populations and enzyme activities, associated with the pesticide type at recommended field application rates. A change in numbers, activity and diversity of soil microorganisms may act as indicators of soil fertility and reflect the soil quality.

The antimicrobial and Phytochemicals activities of methanol extracts obtained from Aloe vera and Hyptis suaveolens plants were investigated individually and combined in an attempt to evaluate their medicinal potentials and efficacies on protozoan; Giardia lamblia and bacteria; Salmonella species as co-infections causing diarrhoea in under five populations in Bauchi State, Nigeria. The phytochemical screening revealed the presence of saponins, tannins, alkaloids, flavonoids, terpenoids, alkaloids, phenols. Antimicrobial activity was determined against Giardia lamblia and Salmonella species; anti-giardial activity, an in-vitro susceptibility assays method was performed and antibacterial activity was carried out by Kirby-Bauer method. The parasites mortality was determined by counting in hemocytometer under a light microscope and the zone of inhibition diameter produced against the bacteria were determined, expressed as mean ±SEM (Standard Error of Mean) and the differences between means were statistically analyzed and compared. The results obtained showed that methanol extracts of Aloe vera and Hyptis suaveolens singly used and in combinations had inhibitory effects on Giardia lamblia and Salmonella species. In all cases, the extractions, plants, concentrations and time were determinant factors for the anti-giardial and antibacterial activity. Anti-giardial activity was best recorded with extracts of Aloe vera which showed anti-giardial activity of (0.002±0.553), and activity was greater in combined Aloe vera and Hyptis suaveolens which showed anti-giardial activity of (0.002±0.679). Also, antibacterial activity of methanol extracts of these plants on Salmonella species, showed higher zone of inhibitions diameter with extracts of Aloe vera (0.895±20.17) and the efficacy becomes higher with the combined Aloe vera and Hyptis suaveolens which zone of inhibitions is (0.423±27.50).