Streptomyces is a bacterial genus represented by over 500 species, a number of which are antibiotic producers. Some studies have reported that 50% of streptomycetes isolated are antibiotic producers. This genus is responsible for the manufacture of over 500 antibiotic substances (2), including chloramphenicol, erythromycin, neomycin, nystatin, streptomycin, and tetracycline (1, 3, 4), which play a major role in the treatment, control, and cure of human and animal diseases and which are used extensively for research (selectivity) in microbiological laboratories.
We have obtained a specimen isolated from pine soil that we believe is Streptomyces and have cross-streaked it with Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus with excellent inhibition. This technique involves streaking one-third trypticase soy agar plate with the test organism and placing cross streaks of known bacterial species in close proximity to it. A clearing on the agar between the test and known bacteria indicates antibiotic production by the test organism.
The colony morphology, cell morphology, and earthy smell are all consistent with this organism. Also, a pathologist at Oregon State University examined the specimen under the microscope and stated that he believed it was Streptomyces.
Precise identification by DNA sequence analysis would tell us which strain we have isolated and, consequently, what antibiotics the strain generally produces. Chemical analysis is probably necessary to definitely identify these antibiotics. We request that funds be allotted for only the DNA sequence analysis at this time to help us narrow the range of possible antibiotics this organism is generating.
1. Madigan, M., Martinko, J., and Parker, J. (1997). "Biology of Microorganisms," 8th ed., p. 736. Upper Saddle River, NJ: Prentice-Hall Inc.
2. Mathews, C. K., and van Holde, K. E. (1996). "Biochemistry," 2nd ed., pp. 1026-1027. Menlo Park, CA: The Benjamin/Cummings Publishing Co.
3. Prescott, L. M., Harley, J. P., and Klein, D. A. (1996). "Microbiology," 4th ed., pp. 498-500. Dubuque, IA: Wm. C. Brown Publishers.
4. Stryer, L. (1995). "Biochemistry," 4th ed., pp. 902-903. New York: W.H. Freeman and Company.
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