Growth and metabolic characteristics of Mycobacterium paratuberculosis

The cultural characteristics of newly isolated strains of Mycobacterium paratuberculosis on a variety of media were studied. The mycobactin dependence ascribed to this species of Mycobacterium was found to be easily circumvented by incorporation of 1% ferric ammonium citrate in serum or egg yolk media, but the earliest and most abundant growth occurred on serum medium that contained mycobactin and sodium pyruvate. In the presence of ferric ammonium citrate, respiration did not decrease during 5 days; but in the presence of all other agents studied, respiration decreased after the first day.