A comparison of the rate of oxygen uptake and the adenosine triphosphate content of routine and experimental BCG preparations.

The ATP content and oxygen uptake rate, two parameters of viability of a BCG suspension, are compared. The lack of correlation between measurements made on fresh routine preparations indicates that the ATP measurements is affected by the degree of dispersion of the preparation. Experimental preparations made under standard conditions (constant semi-dry weight and stepwise dispersive grinding) from cultures of the same age as the fresh routine cultures (14 days) had a smaller ATP content, which correlated well with the respiration rate. In experimental preparations from seven-day cultures this correlation was significant. Between days 7 and 14 the ATP content declined much more rapidly than the respiration rate.