Hey, Good to see you here 😀 …… In this Article, we’re gonna discuss in detail about various biochemical tests for Klebsiella pneumoniae….. If you have any queries, don’t forget to mention in Comments…Thanks
In this Article, we’re gonna discuss so many biochemical reactions for the well known causative agent of UTI (Urinary Tract Infections), Diarrhea & Pyogenic Infections i.e. the Escherichia coli abbreviated as E. coli, but a few reactions are most commonly used and are medically important for distinguishing pathogenic strains of E. coli from other non- pathogenic strains as well as from other species of Escherichia which are as follows:
Methyl Red Positive
Voges – Proskauer Negative
LF colonies on MacConkey agar medium
Unable to produce H2S
Besides that of various biochemical reactions and Sugar fermentation tests, certain enzymatic reactions are also medically important to distinguish Escherichia coli from other Escherichia sp.
Below is the list of these Enzymatic Reactions and various other biochemical tests for Escherichia coli which have great importance in research and for knowledge but are not routinely employed:
Acetate Utilization +VE (POSITIVE)
Alkaline Phosphatase +VE (POSITIVE)
Indole +VE (POSITIVE)
Methyl Red +VE (POSITIVE)
Nitrate Reduction +VE (POSITIVE)
ONPG +VE (POSITIVE)
Catalase -VE (NEGATIVE)
Citrate -VE (NEGATIVE)
Coagulase -VE (NEGATIVE)
DNase -VE (NEGATIVE)
Oxidase -VE (NEGATIVE)
Urease -VE (NEGATIVE)
VP (Voges Proskauer) -VE (NEGATIVE)
Arginine Dehydrolase VARIABLE (As per the Strain)
Escherichia coli and other species of Escherichia ferment various sugars producing acid with gas.
But these sugar fermentation tests are of no diagnostic value in routine laboratory tests except sucrose fermentation test, However, that is also not well understood and some strains are able to ferment sucrose as well, but it can be used in differentiating Escherichia coli, from other Pathogenic & non-pathogenic Escherichia species and Coliform bacteria.
The other sugar fermentation tests which are described below are of great importance in research work.
Arabinose +VE (POSITIVE)
Dextrose +VE (POSITIVE)
Fructose +VE (POSITIVE)
Galactose +VE (POSITIVE)
Glucose +VE (POSITIVE)
Lactose +VE (POSITIVE)
Maltose +VE (POSITIVE)
Mannitol +VE (POSITIVE)
Mannose +VE (POSITIVE)
Melibiose +VE (POSITIVE)
Rhamnose +VE (POSITIVE)
Sorbitol +VE (POSITIVE)
Xylose +VE (POSITIVE)
Adonitol -VE (NEGATIVE)
Dulcitol -VE (NEGATIVE)
Cellobiose -VE (NEGATIVE)
Raffinose -VE (NEGATIVE)
Salicin -VE (NEGATIVE)
Sucrose -VE (NEGATIVE)
Trehalose VARIABLE (depends on strain)
That’s all about the various Biochemical tests for Escherichia coli (E. coli).
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