Über das Verhalten von Colibakterien in Seewasser

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Summary

In contradistinction to experiments on the bactericidal action of sea water upon coliform bacteria in batch cultures growth of Escherichia coli was studied in continuous cultures fed by natural filtered sea water of the Deutsche Bucht. At room temperatures (20° to 22°C) growth of E. coli took place with densities of 10³ cells/ml sea water and with a generation time of about 6 hours. No growth occured at 12° C. Compared with the growth of a marine Vibrio on the same culture conditions. E. coli had a slower growth rate and smaller cell densities. No growth could be observed in sea water if cell densities were about 10¹ cells/ml and smaller. The dilution of the “terrestrial” mass of bacteria in tidal estuaries may cause this physiological effect of the inability to divide — independent of the biological interactions and the bacteriostatic action of temperature. After a continuous run in sea water lasting 5 months no change of the physiological, cultural and morphological characteristics of E. coli Type I, could be observed. That means, no changes occured which possibly could prevent the proof of identity of E. coli in sea water.