Salmonella

Salmonella

Diseases: Typhoid & paratyphoid fevers, food poisoning, enferitis.

Classification of Salmonella:

Classification of salmonella according to pathogenecity:

1. Salmonella that cause enteric fever:
   
   i.  Salmonella typhi.ii. Salmonella paratyphoid –A,B,C.

2. Salmonella that cause food poisoning;
   
   i. Salmonella typhimurium.ii.Salmonella enteritidis.

3. Salmonella that cause septicemia.
   
   i. Salmonella choleratsuis.

Salmonella typhi:

Habitat: Lower part of small intestine.

Morphology of Salmonella typhi:

Shape       :  Rod shaped.

Size          :  2-3 µm

Flagella    : Peritrichous flagella present

Spore       : Absent

Motility   : Motile.

Staining:

They are Gram negative.

Cultural character:

1. Aerobic and facultative anaerobes.
2. Optimum p^H  : 7.2 to 7.6
3. Optimum temperature: 37 °C.
4. Growth on:

i.    Agar culture : Colonies are grayish, transparent & opaque.

ii.   Agar streak: Thin & glistening colonies.

iii.  Broth medium: Uniform growth with turbidity.

iv.  BGA medium: White –snow & flakey colony appear.

v.   End medium : Colorless colony.

vi.  Gelatin stab: White, thin& no liquefaction.

vii. Litmus milk: First acid & then –alkaline growth.

viii.Potato media: Slight moist growth.

ix. Sterile-F – media : Except S.typhi, others are inhibited in growth.

x.  TST agar media : Alkaline slant & acidic butt.

xi. Unease broth : Negative growth .

xii.Wilson –Blair media: blacked colonies.

Biochemical Character of Salmonella typhi:

1. Non-lactose fomenters.
2. Non- urea splitters.
3. Non- in dole producer.
4. All produce acid& gas.