The effect of Ocimum basilicum L. oil on the morphology of E. coli O157:H7 analyzed using scanning electron microscopy

Abstract EN

Three growth phases of E.

coli O157:H7 were identified, i.e.

exponential (0 -8 hours), late exponential (8-16 hours) and stationary phase (16-24 hours).

The morphology of bacteria treated by basil oil were observed under Scanning Electron Microscopy (SEM).

The morphology of normal cells is tightly packed and smooth at the outer surface.

Morphological alterations of E.

coli O157:H7 are shown after treatment with 0.25 mg/ml and 0.5 mg/ml basil oil during exponential, late exponential and stationary phase, respectively.

Some treated cells were irregular in shape, deformed, seen like shrunken cells and obviously damaged by basil oil as compared to untreated cells, while most cells were morphologically normal.

All of cells were not able to growth on medium, these observations support that basil oil killed E.

coli O157:H7 primarily by mechanism(s) other than lysis of cells