Figure 6. Changes in optical density of cultures with S. thermophilus and high initial densities of phage (approx. 5×10⁶/ml) to which the BIMs were resistant.

The first transfers (left) were initiated with 40 µl of overnight bacteria and phage in 4 ml LM17Ca medium. The second transfers (right) were initiated by adding 40 µl of the 24-hour first-pass cultures to 4 ml fresh LM17Ca. Panel A: WT phage with WT cells (medium-weight blue line) and 10 first-order BIMs. Panel B: five second-order BIMs and their corresponding first-order CEM phages. The heavy black lines with square tick marks are phage-free WT controls and the heavy red lines with diamond tick marks are the arithmetic mean densities of all the cultures with phage.