ABSTRACT
Drug resistance against human pathogenic microorganisms has been widely documented in recent years from all over the world. In the world of medicine, Methicillin Resistant Staphylococcus aureus is a big concern. Multiple drug resistance in human pathogenic organisms has required the quest for new antibacterial compounds from non-traditional sources, such as plants. In order to assess the antibacterial action of aqueous extracts of Vernonia amygdalina and Anacardium occidentale against Methicillin Resistant Staphylococcus aureus isolated from dumpsites soils within the University of Benin halls of residence, this study was carried out.
Soil samples were taken randomly from various dumpsites on the Ugbowo campus of the University of Benin. These samples were taken to the laboratory right away for culture analysis on Nutrient Agar, Mannitol Salt Agar and Mueller-hinton Agar. Using oxacillin antibiotics, methicillin resistance was tested in isolated Staphylococcus aureus. Fresh leaves of Vernonia amygdalina and Anacardium occidentale were taken from the University of Benin’s Faculty of Agricultural Science farms. They were air-dried, ground to powder, dispensed into sterile containers, and labeled for aqueous solvent extraction.
The physiochemical assessment of the dumpsite soils showed that pH ranged from 4.81 - 5.82, total organic carbon ranged from 0.48% - 0.56% and had high iron levels of up to 102.3mg/kg. Total heterotrophic bacteria count ranged from 7.70 - 10.30 x104 (cfu/g) compared to the control heterotrophic bacteria count which ranged from 3.30 - 3.90 x104 (cfu/g). Staphylococci count from dumpsite soil ranged from 0.77 - 1.30 x104 (cfu/g). Bacteria isolated from the dumpsite soil includes Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Bacillus sp, Escherichia coli, Enterococcus spand Micrococcus sp. The isolated Staphylococcus aureus was tested for oxacillin resistance to evaluate the status of Methicillin Resistant Staphylococcus aureus (MRSA). Isolates from hall 3 and hall 7 were found to be resistant. Total percentage resistance for the isolated Staphylococcus aureus is 52.6% . All the tested bacterial isolates were susceptible to ciprofloxacin with Staphylococcus aureus isolate from Hall 7 having the highest resistance index (0.5). Quantitative phytochemical compositionof aqueous extracts of Vernonia amygdalina and Anacardium occidentale were phenols, alkaloids, saponnins, tannins, flavonoids and cyanogenic glycoside. The use of aqueous extracts of Vernonia amygdalina and Anacardium occidentale revealed that the extracts were not bactericidal, however possessed bacteriostatic properties. When 100 mg/ml of plant extracts were employed, the zones of inhibition formed ranged from 11.83 mm to 12.33 mm, indicating that the usage of 12.5 mg/ml had no bacteriostatic impact.
