BIOCHEMICAL TESTS FOR SALMONELLA TYPHI (S. TYPHI)

In this Article, I’m gonna discuss various biochemical reactions for the well known causative agent of Enteric fever, Septicemia & Gastroenteritis i.e. the Salmonella typhi abbreviated as S. typhi.

However, only a few reactions are most commonly used and are medically important for distinguishing pathogenic strains of Salmonella typhi from other non- pathogenic strains as well as from other species of Salmonella which are as follows:

⇒ Produces H₂S

⇒ Indole Negative

⇒ Citrate Positive

⇒ Urease Negative

⇒ Methyl red (MR) Positive

⇒ Voges – Proskauer (VP) Negative

⇒ Colorless – NLF colonies on MacConkey agar medium

⇒ Jet black colonies with a metallic sheen on Wilson & Blair bismuth sulfite medium

⇒ Pink or Red Colonies with black center on XLD medium.

Check out the Morphology & Culture Characteristics of Salmonella typhi

Besides that of various biochemical reactions and Sugar fermentation tests, certain enzymatic reactions are also medically important to distinguish Salmonella typhi from other Salmonella sp.

Below is the list of these Enzymatic Reactions and various other biochemical tests for Salmonella typhi which have great importance in research and for knowledge but are not routinely employed:

Salmonella typhi ferments various sugars producing acid only as S. typhi is anaerogenic bacteria making it easy to differentiate from other species of Salmonella which ferment sugars producing acid with gas.

But these sugar fermentation tests are of no diagnostic value in routine laboratory tests except Lactose & Sucrose fermentation test, which is of great importance in differentiating Salmonella typhi, which is unable to ferment Lactose and Sucrose, from other Pathogenic & non-pathogenic Salmonella species.

Check out the Biochemical tests for Klebsiella pneumoniae

BIOCHEMICAL TESTS FOR KLEBSIELLA PNEUMONIAE (K. PNEUMONIAE)

The other sugar fermentation tests which are described below are of great importance in research work.

That’s all about the Biochemical tests for Salmonella typhi.

Further Reading:

Identification of Salmonella typhi and paratyphi – Microbeonline

SAHIL BATRA

Hi, I’m the Founder and Developer of Paramedics World, a blog truly devoted to Paramedics. I am a Medical Lab Tech, a Web Developer and Bibliophiliac. My greatest hobby is to teach and motivate other peoples to do whatever they wanna do in life.