Electron microscopic study of the effects of antimicrobial agents on the cellular architecture of Leptospira

Morphological changes of Leptospira induced by ampicillin, streptomycin, or ciprofloxacin were studied by transmission electron microscopy after staining with uranyl acetate. Irregularities in coiling, loss of hooks, spherical swellings, membrane vesicle formation, disruption of outer membrane, exposure and detachment of flagella, penetration of dye, and lysis of cells were observed. These changes appeared in a time-dependent manner and appeared to be associated with the sites of action of antimicrobial agents. This is the first report delineating the action of aminoglycoside and new quinolone on the morphology of Leptospira cells.