ISSN 2326-7267
International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 7 (2), pp. 001-009, February, 2018. © International Scholars Journals
Full Length Research Paper
In vitro time-kill studies of antibacterial agents from putative marine Streptomyces species isolated from the Nahoon beach, South Africa
Isoken H. Ogunmwonyi 1, Ntsikelelo Mazomba1, Leonard Mabinya1, Elvis Ngwenya1, Ezekiel Green1, David A. Akinpelu2, Ademola O. Olaniran3 and Anthony I. Okoh1*
1Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.
2Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria.
3Division of Microbiology, University of KwaZulu Natal, Durban Westville, South Africa.
Accepted 13 December, 2017
Abstract
We assessed the antibiotic production potentials of ten putative Streptomyces strains isolated from the Nahoon beach and their antibacterial activities against a wide range of bacteria including reference strains, environmental strains and clinical isolates. The minimum inhibitory concentrations (MICs) of the crude ethyl acetate extracts ranged from 0.039 to 10 mg/mL and the least minimum bactericidal concentration (MBC) demonstrated was 0.625 mg/mL against a reference strain Staphylococcus aureus ATCC 6538. Time kill kinetics of all extracts revealed bacteriostatic and bactericidal activities. Average log reductions in viable cell counts for all the extracts ranged from 0.86 log 10 and 3.99 log10 cfu/mL after 3 h interaction and 0.01 log 10 and 4.86 log10 after 6 h interaction at MIC, 2 × MIC, 3 × MIC and 4 × MIC concentrations. Most of the extracts were speedily bactericidal at 3 × MIC and 4 × MIC resulting in over 50% elimination of most of the test bacteria within 3 and 6 h interaction. Our findings suggest that the marine Streptomyces isolated from the Nahoon beach have tremendous potential as sources of new antibacterial compounds.
Key words: Time-kill, antibacterial compounds, Marine streptomyces, Nahoon beach.