Biochemical Test of Shigella flexneri

Reviewed By Prof Walter Jaoko

Shigella flexneri is a species of gram-negative, non-spore-forming bacterium belonging to the genus Shigella. Shigella flexneri is primarily associated with bacillary dysentery, a form of gastroenteritis characterized by severe diarrhea with blood and mucus. Symptoms of shigellosis can include abdominal cramps, fever, and dehydration. The infection is typically transmitted via the fecal-oral route, often through contaminated food or water.

Shigella flexneri appears as small, non-motile, rod-shaped bacteria under the microscope. It is non-spore-forming and typically occurs singly or in pairs. It is a facultative anaerobe and does not ferment lactose. It can be differentiated from other species of Shigella and from Escherichia coli by its ability to ferment mannitol. It is also non-motile.

Shigella flexneri produces several virulence factors that enable it to cause disease. These include invasion plasmid antigens (Ipa proteins), which facilitate invasion of the intestinal epithelium, and Shiga toxin, which can cause severe gastrointestinal symptoms.

Shigella flexneri, like other bacterial species, can be identified and characterized through various biochemical tests.

Basic CharacteristicsProperties (Shigella flexneri)
CatalasePositive (+ve)
CitrateNegative (-ve)
GasPositive (+ve)
Gelatin HydrolysisNegative (-ve)
Gram StainingNegative (-ve)
Growth in KCNNegative (-ve)
H2SNegative (-ve)
MR (Methyl Red)Positive (+ve)
Nitrate ReductionPositive (+ve)
OxidaseNegative (-ve)
PigmentNegative (-ve)
UreaseNegative (-ve)
VP (Voges Proskauer)Negative (-ve)
Fermentation of
AdonitolNegative (-ve)
CellobioseNegative (-ve)
DNaseNegative (-ve)
DulcitolNegative (-ve)
GlycerolNegative (-ve)
LactoseNegative (-ve)
MalonateNegative (-ve)
MannitolPositive (+ve)
MannosePositive (+ve)
MucateNegative (-ve)
MyoInositolNegative (-ve)
RhamnoseNegative (-ve)
SalicinNegative (-ve)
SucroseNegative (-ve)
TrehalosePositive (+ve)
XyloseNegative (-ve)
Enzymatic Reactions
Acetate UtilizationNegative (-ve)
Aesculine HydrolysisNegative (-ve)
Arginine DehydrolaseNegative (-ve)
LipaseNegative (-ve)
LysineNegative (-ve)
ONPG (β-galactosidase)Negative (-ve)
Ornithine DecarboxylaseNegative (-ve)
Phenylalanine DeaminaseNegative (-ve)