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KMID : 0378019690120120083
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New Medical Journal
1969 Volume.12 No. 12 p.83 ~ p.89
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Influences of the growth environments of Staph. aureus upon the viable units number in the blood or urine of rabbits after inoculation.
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Abstract
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The prime object of the medical microbiology may be to understand throughly the exact mechanisms of microbial pathogenicity and to establish the scientific methods by ;which microbial maladies be erradicated or treated without failure. However, the present status of our knowledge, concerning the mechanisms of microbial pathogenicity, is very limited, though it is said that the probable nature of disease processes due to microorganisms is biochemical.
One of the main reason may be that most of the studies on microbial metabolisms have been performed under the certain in vitro conditions which are invariably quite different from the conditions in vivo. The metabolic behavioures were compared between the organisms grown in vivo and in vitro by number of investigators and all of their reports indicated marked differences. The present methodology of the field does not permit to duplicate the in vivo conditions exactly in vitro.
Since it was reported that the biochemical activities of the some bacterial species are different when they are grown under different environments, it was thought worthwhile to investigate the influences of the bacterial growth conditions on the fate of the organisms in tissues of laboratory animals.
Thus, a strain of Staph. aureus was grown in Brain Heart Infusion Broth(BHIB) at 37°C. and 40T., which were supposed to be more or less near the conditions in normal and inflammatory tissues, and also in Peptone water at 22°C., which was supposed to be more or less near the environments in nature. Subcultures of the strain were repeated more than ten times and the growth rates of the cultures were compared. Washed bacterial suspensions of each culture, were inoculated i. v. into rabbits and the number of viable units in the blood and urine were followed.
The results of observations were summarized as follows:
1. The growth rate was most rapid in BHIB at 37T., slowest in Peptone water at 22T., and in BHIB at 40°C. in between them.
2. No significant difference was noticed among the viable units curves of the organisms in the rabbits blood.
3. Viable units of the organisms in the urine of rabbits increased rapidly and continuously for 3 days or more, when the cultures in BIIIB at 37°C. or 40°C. were inoculated. When the culture in Peptone water at 22°C. was inoculated, such rapid increase in early stage was not observed.
4. When the culture in BHIB at:. 37°C. , was inoculated,, the urinary viable units showed marked decreases 5 days after inoculation. When the culture in BHIB at 4000. was inoculated, the viable units in rabbits urine continued to increase, upto 5 days after inoculation.
5. Interrelationships between the growth environments of the microorganisms and the establishments of infection after being introduced into host tissues were discussed.
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