Influence of lomefloxacin on the morphology and ultrastructure of Gram-negative bacterial cells

Abstract

We have studied the effect of lomefloxacin hydrochloride (Maxaquin. Searle, USA) on morphological and ultrastructural changes in the cells of Gram-negative bacteria:Ps. aeruginosa 165,S. typhi 4446,Kl. pneumoniae 444,E. coli KL-16 and KL-166 (laboratory strains), andPs. aeruginosa 5044 (clinical strain). Subbactericidal concentrations of Maxaquin are shown to induce cellular elongation in all the species of bacteria; differences in morphological changes for different microorganism are demonstrated. The elongation ofE. coli andPs. aeruginosa cells mainly occurs via filamentation of the bacterial cell with a sharp disruption of processes of division. In experiments withKl. pneumoniae andS. typhi, filamentous forms tend to be formed to a lesser degree although the elongation effect was sharply pronounced. The formation of scalloped cells and “ghosts” was typical forKl. pneumoniae, with deep ultrastructural changes in the cells recorded under the effect of lomefloxacin (Maxaquin).