Antibacterial Activity of Oxolinic Acid on Pseudomonas glumae

Abstract

Oxolinic acid (5-ethyl-5, 8-dihydro-8-oxo [1, 3] dioxolo [4, 5-g] quinoline-7-carboxylic acid, Starnere^®) is a synthetic bactericide, developed from quinoline derivatives. Oxolinic acid completely inhibited the growth of gram negative bacteria including Pseudomonas glumae, P. plantarii, P. avenae, Erwinia carotovora subsp. carotovora and E. carotovora subsp. atroseptica at the concentration of 0.4μg/ml or below in vitro. Oxolinic acid was effective against various isolates of P. glumae from rice grains collected from various districts of Japan. Antibacterial activities of oxolinic acid on P. glumae varied depending on the growth phase of the bacterium. Activity of oxolinic acid was bactericidal for the bacterium at the lag phase, but was bacteristatic for the bacterium at the early logarithmic phase and decreased after the middle logarithmic phase. Oxolinic acid sometimes induced abnormal elongation of P. glumae cells at the early logarithmic phase.