Purpose: To investigate the effect of the ethyl acetate extract of endophytic fungus,
Nigrospora sphaerica
CL-OP 30 against the growth of methicillin-resistant
Staphylococcus aureus
(MRSA) and
Klebsiella pneumonia
cells.
Methods: Time-kill assay was used to examine the effect of the extract on the bacterial growth profile.
The effects of extract on ultrastructure of MRSA and
K. pneumoniae cells were analyzed by scanning
electron microscope (SEM) and transmission electron microscope (TEM).
Results: The time-kill test revealed that the bacteriocidal activity of the extract was both concentrationand
time-dependent. After 12 h treatment, interaction of extract with MRSA cells resulted in the
formation of pit, disintegration of cell wall and membrane, and ultimately cell death, while
K.
pneumoniae cells became crumpled, and the cell walls and membranes disintegrated, resulting in
leakage of their cytoplasmic contents.
Conclusion: These data suggest that the
Nigrospora sphaerica CL-OP 30 extract principally affects the
cell wall in growing MRSA and
K. pneumonia cells.
