FIG 7.

Pulse dosing results in effective killing of B. burgdorferi persisters. Late exponential cultures of B. burgdorferi were treated with ceftriaxone (Cef) (3 μg/ml) (a) or amoxicillin (Amox) (6 μg/ml) (b) for 5 days. This represents the first round of killing. The cultures were then washed and allowed to recover in fresh BSK-II medium for 24 h. They were then treated again with amoxicillin (6 μg/ml) or ceftriaxone (3 μg/ml) for a further 5 days to give the second round of killing. This was repeated for a total of four rounds of killing with a 24-h period of growth in fresh medium between each round. Bars represent the averages of at least three independent cultures (n = 3 to 6), and error bars represent standard errors. The x axis is the limit of detection. Asterisks represent eradication to the limit of detection.