Carbohydrate Metabolism and Production of Diffusible Active Substances by Staphylococcus aureus Grown in Serum at Iron Levels in Excess of Siderophilin Iron-saturation and Below
SUMMARY: Results of studies are reported on the carbohydrate metabolic capabilities of cells of Staphylococcus aureus grown in human serum at varied percentage iron-saturations of its contained siderophilin; on the production by such cells of coagulase, hyaluronidase, staphylokinase, and haemolysins; and on the effectiveness of some antibiotics as growth inhibitors under similar in vitro growth conditions. Cocci grown in serum at a normal serum iron level and percentage of iron-saturation show a significant reduction in their endogenous respiration, in their capacity to attack lactate, a complete loss of ability to oxidize formate, and a several-fold increase in anaerobic glycolytic capacity as compared to those cocci grown in serum containing unchelated free ionic iron. These metabolic changes, in conjunction with an observed increased rate of acid production and rate of glucose utilization by the growing culture of ‘low-iron’ cells versus the ‘high-iron’ cells, indicate an increased dependence upon glycolytic rather than oxidative energy production processes by the iron-restricted cells. The strain of S. aureus employed in these studies, although characterized by conventional methods as a producer of coagulase, hyaluronidase, haemolysins, and staphylokinase, did not elaborate any of these pathogenesis-linked factors at detectable levels when grown in normal serum. Coagulase, alone, was found at ‘high-iron’ levels. The amount of dimethoxyphenyl penicillin required to inhibit growth of our S. aureus strain grown in serum increased with increasing percentage of iron saturation of the siderophilin while the effectiveness of a given inhibitory concentration of kanamycin and chloramphenicol was indifferent to any variation in the iron-saturation value.
CollinsF. M.,
LascellesJ.1962; The effect of growth conditions on oxidative and dehydrogenase activity in Staphylococcus aureus
. J. gen. Microbiol 29:531
RogersH. J.1954; The rate of formation of hyaluronidase, coagulase and total extracellular protein by strains of Staphylococcus aureus
. J. gen. Microbiol 10:209
SchadeA. L.,
OyamaJ.,
ReinhartR. W.,
MillerJ. R.1954; Bound iron and unsaturated iron-binding capacity of serum; rapid and reliable quantitative determination.. Proc. Soc. exp. Biol. Med 87:443
TheodoreT. S.,
SchadeA. L.1965a; Growth of Staphylococcus aureus in media of restricted and unrestricted inorganic iron availability.. J. gen. Microbiol 39:75
Carbohydrate Metabolism and Production of Diffusible Active Substances by Staphylococcus aureus Grown in Serum at Iron Levels in Excess of Siderophilin Iron-saturation and Below