Assessment of antibiotic production by some marine Streptomyces isolated from the Nahoon Beach

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dc.contributor.authorOgunmwonyi, Isoken Nekpen Henrietta
dc.date.accessioned2016-11-11T15:56:22Z
dc.date.available2016-11-11T15:56:22Z
dc.date.issued2010
dc.description.abstractRapidly emerging strains of bacteria resistant to most advanced antibiotics have become issues of very important public health concern. Research currently directed towards marine actinomycetes presents a vast potential for new compounds that could be able to safely and effectively target resistant species. In this regard, ten putative Streptomyces strains isolated from the Nahoon beach were selected and assessed for antibiotic production and activity against a wide range of bacteria including reference strains, environmental strain and clinical isolates. The ethyl acetate extracts of the putative Streptomyces isolates showed activities against at least 6 and up to 26 of the 32 test bacteria. Inhibition zones were found to range between 9-32 mm diameters at a concentration of 10 mg/ml. The minimum inhibitory concentrations (MICs) of the crude extracts ranged from 0.039 - 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 bacteristatic and bactericidal activities. Average Log reductions in viable cell counts for all the extracts ranged from 0.86 Log10 and 3.99 Log10 cfu/ml after 3 h interaction and 0.01 Log10 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 h and 6 h interaction. The partial characterization of the crude extracts by IR spectral analysis revealed possibility of terpenoid, long chain fatty acids and secondary amine derivatives compounds in the extracts. It is therefore recommended that further investigation should address the relationship between the structure of the active component of the extracts and the broad spectrum activity, as well as a rapid method for large scale production and purification and whether this group of antibiotics has any application in managing human infectious disease..en_ZA
dc.identifier.urihttp://hdl.handle.net/20.500.11837/717
dc.language.isoenen_ZA
dc.publisherUniversity of Fort Hareen_ZA
dc.subjectStreptomycesen_ZA
dc.subjectActinobacteriaen_ZA
dc.subjectGram-positive bacteriaen_ZA
dc.subjectAntibioticsen_ZA
dc.subjectAntibiotics -- Testingen_ZA
dc.subjectDrug resistance in microorganismsen_ZA
dc.subjectNahoon Estuary (South Africa)en_ZA
dc.titleAssessment of antibiotic production by some marine Streptomyces isolated from the Nahoon Beachen_ZA
dc.typeThesisen_ZA

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