Abstract
Crude extracts of four actinomycetes species belonging to Actinoplane [NB 034],Streptomyces [TR 007] and Actinopolyspora [NB 069 and TR 008] genera were screened for antibacterial activities against a wide range of bacterial strains. The extracts showed antibacterial activities against both Gram-negative and Gram-positive test bacteria with zones of inhibition ranging between 2 and 27 mm (NB 034); 9 and 15 mm (TR 007); 8 and13 (NB 069) and 2 and 12 mm (NB 069). The minimum inhibitory concentration (MIC) of the extracts against the test bacteria ranged from 0.039 - 5 mg/ml, while the minimum bactericidal concentrations (MBC) ranged from 5 to >10 mg/ml. The extracts exhibited concentration-time dependent killing of Staphylococcus aureus OKOH2A and Staphylococcus scuiri OKOH2B with a 0.73log10 and 0.88log10reduction in viable counts respectively, while a re-growth phenomenon was exhibited byKlebsiella pneumonia ATCC 4352 and Escherichia coli ATCC 25922 at MIC, 2 × MIC and 4 × MIC of Streptomyces (TR 007) Actinopolyspora (TR 008) extracts. All the active extracts exhibited bacteriostatic activities. Key words: Actinoplane, Streptomyces, Actinopolyspora, antibiotic production.
Highlights
The actinomycetes are Gram positive bacteria having high G+C (>55%) content in their DNA
Actinomycetes from the genera Actinoplane, Streptomyces, and Actinopolyspora have been reported to produce over 300 broad-spectrum antibiotic substances (Kieser et al, 2000; Wynands and van Pee, 2004) and representatives of these genera are widely abundant in aquatic ecosystems
We report on the antibacterial potentials of antibiotic compounds produced by three actinomycetes isolates belonging to the genera Actinoplane, Actinopolyspora and Streptomyces and isolated from the aquatic environment of the Eastern Cape Province of South Africa as part of our ongoing search of new antimicrobial compounds
Summary
The actinomycetes are Gram positive bacteria having high G+C (>55%) content in their DNA. They were originally considered to be an intermediate group between bacteria and fungi but are recognized as prokaryotic organisms which are widely distributed in soil, water and found colonizing plants (Jensen and Fenical, 2000; Ogunmwonyi, 2008). The discovery of new important compounds from common soil-derived actinomycetes as culture extracts yield unacceptably high numbers of previously described metabolites (Mincer et al, 2002). Actinomycetes from the genera Actinoplane, Streptomyces, and Actinopolyspora have been reported to produce over 300 broad-spectrum antibiotic substances (Kieser et al, 2000; Wynands and van Pee, 2004) and representatives of these genera are widely abundant in aquatic ecosystems The need for increased exploration of previously unexplored habitats for new actinomycete taxa has become a major focus in the search for the generation of pharmaceutical agents (Bull et al, 2000), especially with the increasing trend in development of antibiotic resistance in microbial pathogens.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
