South Asian Journal of Research in Microbiology

Background: The leaves and rhizome extracts of Cyperus rotundus Linn. popularly called “Nut grass” in many Nigerian communities have been extensively used in local food preparation and in treatment purposes.

Aim: This study aimed to evaluate the phytochemical contents, proximate nutritional composition and antimicrobial activity of the leaves and rhizome extracts of C. rotundus.

Methodology: The disease-free plant materials were collected from a farm in Uyo, Akwa Ibom State, Nigeria. Preparation of the plant material, methanolic and aqueous extracts; bacterial culture, isolation, microscopy and biochemical identification; phytochemical screening and proximate nutritional analysis were done according to standard methods, while screening for antimicrobial activity was done by agar well diffusion technique.

Results: The preliminary phytochemical analysis of the plant extracts showed the presence of bioactive compounds at varying amounts such as glycosides, tannins, reducing sugars, alkaloids, flavonoids, polyphenols, terpenoids, saponins and phlobatannins. The proximate nutritional and elemental analysis of C. rotundus extracts showed high presence of B-carotene (164.3 ± 0.02), Vitamin A (109.25 ± 0.01) and carbohydrate (59.0 ± 0.01) with moderate content of lipid (24.25 ± 0.02) and moisture (9.10 ± 0.01) as well as contents of some mineral elements such as Ca, K and P occurring in the range literature values in mg per 100 g dry weight of the plant sample. The methanol and aqueous extracts of C. rotundus showed varying diameter of zones of inhibition on the test organism. The observable inhibitory effect of the plant extracts on the test organism was more pronounced with methanol extracts as indicated by the diameter of zones of inhibition in mm in the order of 22.0>14.0>13.0 for P. mirabilis, E. coli and S. aureus, respectively compared to the aqueous extract.

Conclusion: The results of this study have shown the antimicrobial, therapeutic and nutritional potential of the leaves and rhizome extracts of C. rotundus. It could possibly find application as a good alternative antibacterial agent, nutraceuticals and dietary supplements.

The alarming increase of antibiotic resistance of Escherichia coli has posed a great challenge in the public health sector. Thus, this microorganism is a leading cause of different human infections and it can be found in various environments. The aim of this study is to investigate the antimicrobial susceptibility patterns and the multiple antimicrobial resistance profile of Escherichia coli isolates obtained from some hospitals in Abeokuta, Ogun State, Nigeria. Isolates of E. coli were obtained from different clinical samples and were re-identified morphologically and biochemically. E. coli was isolated from 30% out of a total of 70 clinical samples analyzed for isolation and identification. The isolation rate of E. coli was highest in urine samples 10(47.6%) when compared to other clinical samples. There was significant increase in the resistance rate of E. coli to tetracycline (14.3%), ceftazidime (14.2%), and ampicillin (14.2%).Also, an increased sensitivity rate to augmentin (71.4%), ofloxacin (66.7%), cefuroxime (66.7%), ciprofloxacin (61.9%) and ceftazidime (61.9%) were observed. Furthermore, the overall multiple drug resistance rates obtained was 14(66.7%) and it was established that, multiple antimicrobial resistance of the E. coli isolates was plasmid mediated. E. coli isolates exhibited high resistance rate to multiple antimicrobial agents, however, its sensitivity to augmentin, ofloxacin, cefuroxime, ciprofloxacin and ceftazidime showed that these antimicrobials are still effective against E. coli infections in the study area.

Aims: This research was carried out to evaluate the susceptibility patterns of some enteric bacteria to aqueous, ethanol and methanol extracts of Annona muricata leaf.

Study Design: Experimental design.

Place and Duration of Study: Department of Microbiology, Federal University of Technology, Akure, Ondo State, Nigeria. Between January, 2019 and May, 2019.

Methodology: Extraction of bioactive components of leaves was done by maceration and phytochemical screening was carried out on the leaf extracts to determine the bioactive components present. The bacteria isolates were subjected to antibiotic sensitivity test using standard methods while the  antibacterial  activity  of  the  plant  extracts on human enteric bacteria was  determined  using  agar well dilution method. A. muricata bark extracts were purified using column chromatography method. The minimum inhibitory and minimum bactericidal concentrations (MIC/MBC) of the extracts was performed using tube dilution technique.

Results: The phytochemical screening of leaf extracts showed presence of saponins, tannins, flavonoids, terpenoid and glycosides. Antibacterial activities of the leaf extracts revealed that aqueous, ethanol and methanol extracts had highest zone of inhibition of 22.00±0.58 mm, 24.67±0.33 mm and 24.00±0.58 mm respectively on Salmonella typhi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) for ethanol extract ranged between 25-100 mg/ml and 50-200 mg/ml respectively while methanol extract ranged between 25-50mg/ml and 50-100 mg/ml respectively. Ciprofloxacin (CPX) was significantly (P≤0.5) the most active of all the antibiotics used against the test organisms (both clinical and typed isolates).

Conclusion: This research revealed that A. muricata leaf extracts possesses antibacterial activity against human enteric bacteria isolates used in this study. The commercial antibiotics were observed to be effective in inhibiting the test organisms. The purified extracts of A. muricata leaf showed higher inhibitory effect compared to crude extracts which can serve as ingredient for the production of novel antibacterial agents for the treatment of infections caused by enteric bacteria.

Aims: This research is essentially on the Molluscicidal assessment of Aqueous extract of Moringa oleifera Lam seed on Bulinus Snail for the control of Schistosomiasis.

Study Design: This is a controlled study where a total of 810 Bulinus snails were collected from three different streams with each stream representing a community from each of the three senatorial zones of Anambra state where schistosomiasis was endemic. Aqueous extract of Moringa oleifera (Lam) seed at different concentrations were used on the Bulinus snails to determine their molluscidal properties.

Place and Duration of Study: Two hundred and Seventy (270) Bulinus snails were collected from streams representing each of the three senatorial zones of Anambra state viz; Obutu Lake, Omogho town, Orumba North Local Government Area (Anambra South), Agulu Lake, Agulu town, Aniocha Local Government Area (Anambra Central) and Omambra River, Omor town, Ayamelum Local Government Area (Anambra North) This research was carried out between November 2018 to April 2019.

Methodology: Aqueous dilutions of the grinded Moringa oleifera (Lam) seed were exposed to the Bulinus snails from the various streams for 24 hours, after which the snails were removed from the experimental test solution and washed thoroughly with dechlorinated tap water and transferred to containers with fresh dechlorinated tap water for another 24 hours of recovery. The snails were incubated at 28 ± 5°C and fed with lettuce leaves.

Results: Aqueous Moringa oleifera Lam seed extract was toxic to Bulinus adult snails in a dose dependent manner and the total Lethal Concentration (LC₅₀ and LC₉₀) values determined after 24 hours exposure from the whole streams were 468 ppm and 813 ppm respectively.

Conclusion: Aqueous seed extract of Moringa oleifera Lam was toxic to Bulinus snail even at low concentrations.

Introduction: Increased rates of pesticide misapplication and follow-on concerns on public health have become subjects of countless distress. The occurrence of pesticides in soils could result in modifications in soil physical, chemical as well as biological properties hence the need for ways to reduce such impacts.

Research Gap: Insufficient literatures on extensive identification of pesticides’ degraders from non-impacted soils. Existing literatures are restricted to a particular microbial group (bacteria or fungi).

Aim: The study aimed at isolating, characterizing and testing bacteria, moulds, yeasts and actinomyces from soil for the biodegradation of pesticides.

Place and Duration of Study: The study was carried out at the Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun and Federal Institute of Industrial Research, Oshodi, Lagos, Nigeria/ four months.

Methodology: Carbofuran and Paraquat degrading microorganisms were isolated from a non-pesticides impacted soil using mineral salt medium (MSM). The MSM composed in grams per liter: K₂HPO₄, 4.8; KH₂PO₄, 1.2; NH₄NO₃, 1.0; MgSO₄ 7H₂O, 0.2; Ca(NO₃)₂ .4H₂0, 0.4, and Fe(SO₄)₃, 0.001 supplemented with 2 mM Carbofuran or Paraquat as the only carbon source. The ability of the microbial isolates to utilize Carbofuran and Paraquat was screened on MSM containing 150 part per million of the pesticides as the only carbon source. The isolates were identified using the analytical profile index (API), microscopic and macroscopic characteristics.

Results: Bacterial species identified were Bacillus, Pseudomonas, Kocuria, Enterobacter, Chryseobacterium, Corynebacterium, Acinetobacter, Paenibacillus, Lerclercia and Proteus. Actinomyces were Actinomyces isrealii, Actinomyces naeslundi, Actinomyces viscosus 1, Actinomyces meyeri and Actinomyces viscosus 2. Yeast isolates were Candida stellatoidea, Candida krusei and Saccharomyces cerevisiae while moulds were Talaromyces, Cladosporium carionii and Curvularia species.

Conclusion: These findings indicated that Carbofuran and Paraquat degrading organisms are readily extant in soils and can be used to facilitate the removal of these pesticides from such polluted environments.