title: Antibiotic producing potentials of three freshwater actinomycetes isolated from the Eastern Cape Province of South Africa.
abstract: Crude extracts of three actinomycetes species belonging to Saccharopolyspora (TR 046 and TR 039) and Actinosynnema (TR 024) genera were screened for antibacterial activities against a panel of several bacterial strains. The extracts showed antibacterial activities against both gram-negative and gram-positive test bacteria with inhibition zones ranging from 8 to 28 mm (TR 046); 8 to15 mm (TR 039); and 10 to 13 mm (TR 024). The minimum inhibitory concentrations ranged from 0.078 to 10 mg/mL (TR 046); 5 to >10 mg/mL (TR 039); and 1.25 to 5 mg/mL (TR 024). Time-kill studies revealed that crude extract of TR 046 showed strong bactericidal activity against Bacillus pumilus (ATCC14884), reducing the bacterial load by 10(4) cfu/mL and 10(2) cfu/mL at 4x MIC and 2x MIC, respectively, after 6 h of exposure. Similarly, against Proteus vulgaris (CSIR 0030), crude extract of TR 046 achieved a 0.9log(10) and 0.13log(10) cfu/mL reduction at 5 mg/mL (4x MIC) and 1.25 mg/mL (2x MIC) after 12 h of exposure. The extract was however weakly bactericidal against two environmental bacterial strains (Klebsiella pneumoniae and Staphylococcus epidermidis); and against Pseudomonas aeruginosa (ATCC 19582): the extract showed bacteriostatic activities at all concentrations tested. These freshwater actinomycetes appear to have immense potential as a source of new antibacterial compound(s).
authors: Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa; E-Mails: 200904877@ufh.ac.za (T.S.); lmabinya@ufh.ac.za (L.V.M.); nmazomba@ufh.ac.za (N.M.).
authors: Timothy
authors: T
authors: Sibanda
authors: Leonard V
authors: LV
authors: Mabinya
authors: Ntsikelelo
authors: N
authors: Mazomba
authors: David A
authors: DA
authors: Akinpelu
authors: Kim
authors: K
authors: Bernard
authors: Ademola O
authors: AO
authors: Olaniran
authors: Anthony I
authors: AI
authors: Okoh
mesh_terms: D039903:Actinobacteria / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000494:pharmacology*; D005618:Fresh Water / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D013019:South Africa; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents