Objective:To isolate,evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana,Ethiopia.Methods:A total of 31 strains of actinomycetes were isolated and tested agains...Objective:To isolate,evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana,Ethiopia.Methods:A total of 31 strains of actinomycetes were isolated and tested against Gram positive and Gram negative bacterial strains by primary screening.In the primary screening.11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude extracts.The fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc and agar well diffusion methods.The isolates were characterized by using morphological,physiological and biochemical methods.Results:The result obtained from agar well diffusion method was belter than disc diffusion method.The crude extract showed higher inhibition zone against Gram positive bacteria than Cram negative bacteria.One-way analysis of variance confirmed most of the crude extracts were statistically significant at 95%confidence interval.The minimum inhibitor)concentration and minimum bactericidal concentration of crude extracts were 1.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus,and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli respectively.The growth of aerial and substrate mycelium varied in different culture media used.Most of the isolates were able to hydrolysis starch and urea:able to survive at 5%concentration of sodium chloride:optimum temperature for their growth was 30°C.Conclusions:The results of the present study revealed that freshwater actinomycetes of Luke Tana appear to have immense potential as a source ol antibacterial compounds.展开更多
Objective:To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcia aureus(S.auerus) strains against some conventional and traditional antibiotics. Methods:Thirty post operative pa...Objective:To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcia aureus(S.auerus) strains against some conventional and traditional antibiotics. Methods:Thirty post operative pathogenic isolated S.aureus strains were used in this study. Bacterial culture was done in Mueller-Hinton broth at 37 ℃.Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin,urea,galactose, starch and protein,and fermentation of lactose and sucrose.Antibiotic susceptibility were carried out by minimum inhibilory concentration test,minium bactericidal concentration test,disc agar diffusion test and brain heart infusion oxacillin screening agar.Results:Prom this study,it was observed that 100%S.aureus isolates showed positive results in gelatin,urea and galactose hydrolysis test.50%isolates were positive in starch hydrolysis test,35%in protein hydrolysis test. 100%isolates in lactose fermenting test,but no isolate was positive in sucrose fermenting test. Antibiotic susceptibility testing suggested that 20%of isolates were resistant to kanamycin and 46.67%were resistant to oxacillin.Conclusions:These findings show that all these isolates have gelatin,urea,galactose hydrolysis and lactose fermenting activity.20%of these isolates were resistant to kanamvcin and 46.67%were resistant to oxacillin.展开更多
基金Supported by University of Gondar under Teaching and Learning Program(UoG/Budget code:6417)
文摘Objective:To isolate,evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana,Ethiopia.Methods:A total of 31 strains of actinomycetes were isolated and tested against Gram positive and Gram negative bacterial strains by primary screening.In the primary screening.11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude extracts.The fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc and agar well diffusion methods.The isolates were characterized by using morphological,physiological and biochemical methods.Results:The result obtained from agar well diffusion method was belter than disc diffusion method.The crude extract showed higher inhibition zone against Gram positive bacteria than Cram negative bacteria.One-way analysis of variance confirmed most of the crude extracts were statistically significant at 95%confidence interval.The minimum inhibitor)concentration and minimum bactericidal concentration of crude extracts were 1.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus,and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli respectively.The growth of aerial and substrate mycelium varied in different culture media used.Most of the isolates were able to hydrolysis starch and urea:able to survive at 5%concentration of sodium chloride:optimum temperature for their growth was 30°C.Conclusions:The results of the present study revealed that freshwater actinomycetes of Luke Tana appear to have immense potential as a source ol antibacterial compounds.
基金Supported by a grant from Department of Biotechnology,India(No:BT/PR10861/NNT/28/131/2008)
文摘Objective:To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcia aureus(S.auerus) strains against some conventional and traditional antibiotics. Methods:Thirty post operative pathogenic isolated S.aureus strains were used in this study. Bacterial culture was done in Mueller-Hinton broth at 37 ℃.Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin,urea,galactose, starch and protein,and fermentation of lactose and sucrose.Antibiotic susceptibility were carried out by minimum inhibilory concentration test,minium bactericidal concentration test,disc agar diffusion test and brain heart infusion oxacillin screening agar.Results:Prom this study,it was observed that 100%S.aureus isolates showed positive results in gelatin,urea and galactose hydrolysis test.50%isolates were positive in starch hydrolysis test,35%in protein hydrolysis test. 100%isolates in lactose fermenting test,but no isolate was positive in sucrose fermenting test. Antibiotic susceptibility testing suggested that 20%of isolates were resistant to kanamycin and 46.67%were resistant to oxacillin.Conclusions:These findings show that all these isolates have gelatin,urea,galactose hydrolysis and lactose fermenting activity.20%of these isolates were resistant to kanamvcin and 46.67%were resistant to oxacillin.
