Mechanism of action of tetracaine hydrochloride against Pseudomonas aeruginosa.

The mode of action of tetracaine hydrochloride in vitro on Pseudomonas aeruginosa was investigates. The inhibitory and bactericidal action of tetracaine hydrochloride in vitro was adversely affected by magnesium ions. Observation of cellular lysis, leakage of intracellular materials, dehydrogenase activity, and a higher sensitivity of spheroplasts than of whole cells to tetracaine led to the conclusion that tetracaine acts by damaging the cell membrane. The lytic action of lysozyme was potentiated by tetracaine; this finding indicates enhanced permeability of the cell wall. Alteration of cell wall permeability was demonstrated by the finding that the cells exposed to subinhibitory amounts of tetracaine became susceptible to otherwise ineffective erythromycin.