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Cephalexin‐Induced Morphological Alterations in the Surface Structures of Staphylococcus aureus and Escherichia coli Demonstrated by Scanning Electron Microscopy
Author(s) -
Nishino Takeshi,
Nakazawa Shozo
Publication year - 1973
Publication title -
japanese journal of microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0021-5139
DOI - 10.1111/j.1348-0421.1973.tb00789.x
Subject(s) - staphylococcus aureus , spheroplast , escherichia coli , scanning electron microscope , electron microscope , cell wall , microbiology and biotechnology , biophysics , morphology (biology) , chemistry , bacterial cell structure , biology , bacteria , biochemistry , materials science , genetics , physics , optics , composite material , gene
The scanning electron microscope was used to investigate the alterations in surface morphology of Staphylococcus aureus 209P and Escherichia coli NIH induced by the action of cephalexin known to interfere with cell‐wall synthesis. Exposure to cephalexin produced a series of changes on the surface morphology in proportion to the concentrations of cephalexin added. Untreated S. aureus cells had smooth contours. Exposure to 1 μg/ml of cephalexin during the logarithmic phase of growth in S. aureus did not produce any detectable changes. Upon exposure of S. aureus to 5 μ/ml or 10 μg/ml, some cells were larger than normal and showed abnormal cell division‐like structures in part. When S. aureus was exposed to 50 μg/ml, cell division was completely inhibited, and no formation of grape‐like clusters was observed. Untreated E. coli cells appeared to have smooth and regular contours. E. coli propagated almost normally upon exposure of the organisms to 1 μg/ml of cephalexin. Filamentous structures were observed with the exposure of E. coli to 12.5 μg/ml or 25 μg/ml, but spheroplast‐like structures were not observed. Exposure to 100 μg/ml of cephalexin resulted in the formation of marked filamentous cells and spheroplast‐like structures having multiple small saccular outpouchings. Scanning electron microscope demonstrated more completely the morphological abnormalities induced by cephalexin.