TL;DR: It has been shown that M. tuberculosis inoculated inito modified Kirchner's medium may be grown in an agitated or aerated environment and shake cultures yield greater dispersion of cellular aggregates and an increase in the number of cells after seven days in this medium.

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Abstract: 1949) or Dubos' medium (Dubos and Davis, J. Exptl. Med., 83, 409, 1946) wxere inoculated with 0.6 ml of a 7 day old actively growinlg H37Rv culture and incubated at 37 C. A portion of the flasks were agitated at 240 oscillations per minute on a constant speed rotary action shaker. Other flasks were shaken manually once daily or not at all; these served as controls. The variation of pH during growth was uniform with all samples tested. At intervals, 10 ml samples of these cultures were transferred to standard tubes and turbidities measured with a \"lumetron\" colorimeter (580 m,u). Results are shown in figure 1. Values read from dry weight standard curves iindicated that shake cultures in modified Kirchner's medium, after 10 days, produced 5 mg of cells per 10 ml medium as compared to 4 mg developed in cointrol flasks in the same time period. Similar results were produced by agitation with a stream of sterile air. No stain-ing differences were observed between the shaken and nonshaken bacteria. The organiisms grew in the shaken cultures with modified Kirchner's medium in smaller and more compact aggregates, similar to the type of growth usually obtained with various fungi. The stationary cultures showed typical rope-like arrangements. Organisms grown in Dubos' medium showed less turbidity wNhen shaken than -when manually agitated. In both instances growth was much less than in modified Kirchner's medium. Turbidity readings of cultures growvn in modified Proskauer-Beck medium (Youmans, .J. Bact., 51, 703, 1946) were niot possible because strain H37Rv, regardless of physical environment, assumes a flocculent type of growth. Thus, it has been shown that M. tuberculosis inoculated inito modified Kirchner's medium may be grown in an agitated or aerated environment. Although it seems that growth by these methods is not more rapid, shake cultures yield greater dispersion of cellular aggregates and an increase in the number of cells after seven days in this medium.

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