Effect of nalidixic acid on the morphology and protein expression of Pseudomonas aeruginosa

Objective: To determine the effect of nalidixic acid on the morphology and protein expression of Pseudomonas aeruginosa (P. aeruginosa). Methods: Nalidixic acid solution of 1 600 μg/mL was prepared. The minimum inhibitory concentration (MIC) for P. aeruginosa was determined with tube dilution test. The effect of nalidixic acid on the morphology of P. aeruginosa was studied using light microscope and scanning electron microscope. Changes in protein profile were studied using SDS-PAGE. Results: The MIC of nalidixic acid was 700 μg/mL against P. aeruginosa. The exposure of P. aeruginosa to different concentrations of nalidixic acid resulted in deformation of most of the growing cells. At the concentration of 600 μg/mL most of the cells turned into elongated and adhere to each other while some of the cells were bulged. The intensity of protein bands were changed when they exposed to nalidixic acid. Conclusions: The present findings suggest that the morphology and protein expression of P. aeruginosa is greatly affected by nalidixic acid.