Continuous spore disruption using radially focused, high-frequency ultrasound

We report on the development of a novel, continuous-flow, radially focused ultrasonic disruptor capable of lysing Bacillus spores in the absence of ad ded chemical denaturants, enzymes, or microparticles. Greater than 99% disr uption was achieved for Bacillus globigii spores and Escherichia coli and B acillus subtilis vegetative cells with sample residence times of 62, 12, an d 12 s, respectively. Microscopic and SEM images indicated that at equivale nt power levels, the incidence of cell death or loss of viability typically exceeded the efficiency of (visible) cell lysis. However, semiquantitative PCR showed up to a 1000-fold increase in intracellular DNA availability fr om ultrasonically disrupted spores, and liberated DNA was intact and availa ble for subsequent detection.