Saprophytic soil bacteria

Mycobacteria. Most mycobacterial species seem to be harmless saprophytic soil bacteria of the grampositive group. However, tuberculosis (caused by Mycobacterium tuberculosis) may infect one-third of the inhabitants of the earth603 and kills about three million... 

The development of useful monohactum antibiotics begun with the independent isolation of sulfazecin (SQ 26,445) and other monocyclic /3-luctam antibiotics from. saprophytic soil bacteria in Jupun "" and the United States."" Sulfazecin was found to he weakly active as an antibacterial agent but highly resistant to -lactamiLses. 

There are many different nitrogen sources Some molds yeasts and bacteria are able to utilize inorganic nitrogen, e.g. nitrate or ammonium salts Certain soil bacteria can even assimilate atmospheric nitrogen. Other saprophytes require organic nitrogen in the form of amino acids peptones or proteins. 

The importance to pathogenic bacteria of organic residues in soil other than the dead tissues of the plants attacked by the bacteria is not fully known. Certainly some of these organisms can obtain their energy from these residues but considering the speed with which most of them die it seems probable that this is not a very satisfactory food source. In fact, Burkholder (1948) states that none of the species has been shown to attack cellulose, and only a few can hydrolyze starch. Some of them live on the roots of plants that they do not attack parasitically. Since they all live in close association with other common soil inhabitants it is likely that they make use of bits of substances formed by this mass of soil saprophytes. Such an associative action could account for the survival of... 

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