Microbial effects of manure from poultry droppings and pig dung in diesel-contaminated soil.

In recent years, an increase in environmental pollution has been observed due to rapid industrialization, unsafe agricultural practices, and increased human activities on energy reservoirs. The wide use of petroleum hydrocarbon products as energy sources has contaminated the soil and the environment, thereby posing serious threats to all life forms, including humans. This study aimed to investigate the role of poultry droppings and pig dung in enhancing the bioremediation of diesel-contaminated soil. Soil samples were collected, processed by air drying and sieving, weighed in experimental bowls (5000 g), and contaminated with 250 ml of diesel. Then, poultry droppings and pig dung were added to the soil samples in different ratios, namely 1 : 1, 1 : 2, and 2 : 1. The diesel-contaminated soil sample without treatment served as the control. Thirty days after exposure to the experimental treatment regimes, the total bacterial count and the hydrocarbon-utilizing bacterial count of the diesel-contaminated soil ranged from 0.4 × 104 to 2.7×104 CFU/g and from 0.1×104 to 2.1×104 CFU/g, respectively. The total fungal count and the hydrocarbon-utilizing fungi count ranged from 0.6 × 103 to 2.1×103 SFU/g and from 0.2×103 to 1.7×103 SFU/g, respectively. Bacillus subtilis, Micrococcus sp., Pseudomonas aeruginosa, Proteus vulgaris, Aspergillus niger, Penicillium sp., and Mucor sp were found to be active degraders. A significant reduction in the total aliphatic hydrocarbon (TAH) content of the diesel-contaminated soil was reported, with remediation approaching 95% in 30 days when the poultry droppings - pig dung mixture was added to the soil. The remediation of diesel-contaminated soils is important for the enhancement of the ecosystem. This study has shown that the use of farm waste such as the poultry droppings - pig dung mixture can enhance the remediation of diesel-contaminated soils.

Evaluation of the Phenolic Content, Antioxidant and Antimicrobial Activities of Oil and Non-Oil Extracts of Citrus sinensis (L.) Osbeck Seeds.

The seeds of Citrus sinensis (L.) Osbeck (sweet orange) are waste products usually discarded. They may however contain phytochemicals that have potent bioactivities. In this study, the phenolic content, and antioxidant and antimicrobial activities of oil and non-oil (solid) extracts of C. sinensis seeds were evaluated using standard protocols. The seed oil contained significantly (P>0.05) higher contents of total phenol and total flavonoid when compared to the solid extract. However, the non-oil extract contained significantly (P<0.05) higher tannin contents than the seed oil. Ferric reducing antioxidant potential was not significantly different between both extracts. The antimicrobial activities of both extracts revealed that the seed oil possesses better antibacterial activities compared to the non-oil extract. The antifungal test revealed that the seed oil significantly inhibited the growth of Candida albicans (20 mm zone of inhibition at a concentration of 200 µg/mL), however, it did not inhibit the growth of Aspergillus niger and Penicillum sp. The minimum inhibitory concentration values against the bacterial and fungal strains were similar for both extracts in the range of 50∼100 µg/mL. Minimum bactericidal concentration and minimum fungicidal concentration values ranged from 100∼200 µg/mL for both extracts. The results in this study indicate that C. sinensis seed oil and non-oil extracts possess antioxidant, and antibacterial and antifungal properties that may be differentially exploited in the development of antimicrobial agents.

Prevalence of Methicillin-Resistant Staphylococcus aureus and Other Staphylococcus Species in Raw Meat Samples Intended for Human Consumption in Benin City, Nigeria: Implications for Public Health.

The present study was designed to characterize methicillin-resistant staphylococci from raw meat. A total of 126 meat samples were obtained from open markets between February and April, 2015. Antimicrobial susceptibility testing was carried out using the disc diffusion method. Molecular profiling was conducted using 16S rRNA, mecA, nuc, and PVL gene signatures were detected by polymerase chain reaction assay. Fifty isolates of methicillin-resistant Staphylococcus spp. were detected in 26 (52%) pork, 14 (28%) beef and 10 (20%) chicken samples. The staphylococcal isolates were identified through partial 16S ribosomal ribonucleic acid (16S rRNA) nucleotide sequencing, and BLAST analysis of the gene sequence revealed 98%-100% staphylococcal similarity. All isolates from beef and chicken samples amplified the mecA gene, while 100% of the MRSA isolates amplified the PVL gene. The multidrug resistance profile (resistant to ≥1 antimicrobial agent in ≥3 classes of antimicrobial agents) of the staphylococcal isolates showed that 7 isolates were resistant to methicillin, penicillin, clindamycin, chloramphenicol, trimethoprim-sulfamethoxazole, kanamycin, amoxicillin, cloxacillin, erythromycin, vancomycin, and gentamycin. There was a significant regression effect from the multidrug-resistant profile on the number of isolates (p < 0.05) suggesting a consequence of the dissemination of resistant strains within bacterial populations. The findings of the present study indicate that raw meats in the Benin metropolis were possibly contaminated with pathogenic and multi-drug resistant staphylococci strains and therefore could constitute a risk to public health communities.

Phytochemical, antimicrobial, and antioxidant activities of different citrus juice concentrates.

The search for new antimicrobial compounds is ongoing. Its importance cannot be overemphasized in an era of emerging resistant pathogenic organisms. This study therefore investigated the phytochemical composition and antioxidant and antimicrobial activities of different citrus juice concentrates. Fruit juices of Citrus tangerine (tangerine), Citrus paradisi (grape), Citrus limon (lemon), and Citrus aurantifolia (lime) were evaluated. Antimicrobial activities against five bacterial and three fungal strains were evaluated. The results revealed the presence of alkaloids, flavonoids, steroids, terpenoids, saponins, cardiac glycosides, and reducing sugars in all the juice concentrates. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacities varied with tangerine and grape juices having better scavenging capacities than lemon and lime juices. Grape juice was observed to have a significantly higher (P < 0.05) ferric-reducing antioxidant potential (FRAP) value (364.2 ± 10.25 µmol/L Fe(II)/g of the extract) than the reference antioxidant, ascorbic acid (312.88 ± 5.61 µmol/L). Antimicrobial studies revealed differential antimicrobial activities against different microbial strains. Zones of inhibition ranging from 4 to 26 mm were observed for the antibacterial tests with 0-24 mm for antifungal test. Minimum inhibitory concentrations (MIC) and minimum bacteriostatic concentrations (MBC) for concentrates against bacterial strains ranged from 12.5 to 200 µg/mL. Lemon and lime juice concentrates had lower MIC and MBC values with orange and tangerine having the highest values. Minimum fungicidal concentrations ranged from 50 to 200 µg/mL. The results of this study suggest that these juice concentrates may have beneficial antimicrobial roles that can be exploited in controlling unwanted microbial growth.