Ultrasonic disintegration of bacteria may lead to irreversible inactivation of β-lactamase

When ultrasonic disintegration of bacteria was employed to liberate intracellular β-lactamases there was rapid and irreversible inactivation of the type-Id β-lactamase from Pseudomonas aeruginosa. Various type-V β-lactamases (PSE-2, 3 and 4) from P. aeruginosa, as well as Enterobacter cloacae type-Ia β-lactamase were much less affected by sonication. None of the β-lactamases was inactivated by French Press disruption. We suggest that French Press disruption should be the method of choice for the release of β-lactamases, unless the enzyme in question is known to be unaffected by ultrasonic treatment.