Factors Influencing the Growth of Rickettsiæ
| Autor: | Joseph E. Smadel, Elizabeth B. Jackson, Ross L. Gauld |
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| Rok vydání: | 1947 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 57:273-284 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.57.3.273 |
| Popis: | Summary Streptomycin produced a rickettsiostatic effect in embryonated eggs infected with R. prowazeki, R. mooseri, D. rickettsi, or R. akari, but had little or no effect on R. orientalis in the doses employed. This effect was demonstrable in some instances with amounts as small as 1 mg per egg, a dose which results in a concentration in embryo and fluids of about 2 mg per cent. Although the results in such experiments were statistically significant, the actual prolongation of life in the group of treated embryos was not great. On the other hand, the administration of 10 mg per egg resulted in a distinct lengthening of life of embryos infected with the four organisms. Experiments in which preparations of streptomycin containing different amounts of impurities were employed, and others in which the bacteriostatic activity of the materials was reduced by treatment with semicarbazide, seemed to indicate that the antibacterial and antirickettsial effect of the substance went hand in hand. Dihydrostreptomycin had some rickettsiostatic activity but it is less than that of streptomycin. Combined treatment of embryos infected with the four susceptible rickettsiæ with 10 mg of streptomycin and 0.5 mg of para-aminobenzoic acid resulted in a more striking inhibition of growth than was obtained with similar amounts of either drug alone. In a like manner, 10 mg of streptomycin and 0.4 mg of nitroacridine displayed an additive effect in embryos infected with R. mooseri and D. rickettsi. The possible usefulness of this synergy in the treatment of rickettsial infections in man is postulated. Several biologically active materials, namely, tryptophan, riboflavin, folic acid and two of its related compounds, had no demonstrable effect in the amounts employed on the growth of rickettsiæ in embryonated eggs. Furthermore, these substances did not influence the rickettsiostatic effect of paraaminobenzoic acid when tested under similar conditions. |
| Databáze: | OpenAIRE |
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