51. Genus Salmonella (taxonomy, habitat, morphology, culture).

Question 1

Taxonomy?

Answer 1

SALMONELLA Taxonomy:

• species: • S. enterica • S. bongori
• within S. enterica • 6 subspecies • S. enterica subsp. enterica • S. enterica subsp. arizonae
• within subspecies • serovars/serotypes, (binominal names): 2500 • e.g.: S. enterica subsp. enterica serovar Typhimurium • S. Typhimurium

Question 2

Habitat?

Answer 2

Habitat:

• gut • sewage, water • feed • food

Question 3

Morphology?

Answer 3

Morphology:

• 1-5 µm rod, flagella
• except: S. Gallinarum / S. Pullorum

Question 4

Staining?

Answer 4

. Staining: • Gram-negative

Question 5

Culture?

Answer 5

Culture:

• not fastidious
• selective and differential media are used

• low selective capacity • MacConkey, Drigalski: lactose negative

• medium selective capacity • brilliant green-lactose-phenol red: lactose negative • XLD (xylose-lysine-decarboxilase): lactose negative, H2S • Rambach agar: fermentation of propylene glycol
• high selective capacity • bismuth-sulphite agar: reduction

Question 6

Culture 2?

Answer 6

Culture:

• selective enrichment

• aim

• isolation of Salmonella from mixed flora
• low number of Salmonella
• media • Na-selenite, cystine
• Na-tetrathionate, bile salts
• Rappaport-Vassiliadis (ph 5.2; higher osmotic pressure)