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Carbohydrate Metabolism of Iron-Rich and Iron-Poor Staphylococcus aureus
Abstract
SUMMARY
Comparative studies were made of the metabolic activities of a strain of Staphylococcus aureus grown in iron-poor and iron-rich trypticase medium, with and without glucose. Four nutritionally distinctive types of organisms were produced: iron-rich without glucose (Fe + G –); iron-poor without glucose (Fe– G –); iron-rich with glucose (Fe + G + ); iron-poor with glucose (Fe– G+). Fe+ G– cocci oxidized glucose, l- and d-lactate, pyruvate, acetate, formate, and Krebs cycle intermediates to completion. Of these substrates, only glucose and the lac-tates were oxidized by the Fe– G– organisms. These latter oxidations proceeded at decreased rates and incompletely to acetate and acetoin. Fe+ G+ cocci in comparison with the Fe+ G– cocci showed glucose inhibition of oxidative capacity by metabolizing only glucose, L-lactate and pyruvate to acetate and failing to oxidize d-lactate, acetate and Krebs cycle intermediates. The Fe– G+ cocci showed the most severe restriction of oxidative capacity by oxidizing only glucose with the accumulation of much lactate and minor amounts of pyruvate, acetate and acetoin. The Fe – G –, Fe – G +, and Fe + G + cocci glycolysed glucose at comparable rates, while the highly oxidative form Fe+ G– showed a markedly decreased glycolytic activity. The catalase activity of both types of iron-poor cocci was very much lower than that of the iron-rich organisms. Of the latter, the Fe+ G+ cocci showed a catalase activity only 20% that of Fe + G – cocci.
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© Society for General Microbiology 1965