SALMONELLA SHIGELLA AGAR

Technical Data #1127a / 2013.11.01

The Salmonella Shigella Agar is a selective medium for isolation of Salmonella and Shigella from stool and food products. Brilliant green, bile salts, sodium thiosulfate and citrate are the selective agents. A colony with black center confirm H2S production by thiosulfate reduction.

 


 

FORMULA
in grams per liter purified filtered water

Beef Extract

5,0

Casein Peptone

2,5

Meat Peptone

2,5

Lactose

10,0

Bile Salts

8,5

Sodium Citrate

8,5

Sodium Thiosulfate

8,5

Ferric Citrate

1,0

Neutral Red

0,025

Brilliant Green

0,00033

Agar

13,5

pH 7,0 +/- 0,2 25 C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8 C protected from direct light and dehydrated powder, in a dry place, in tightly-sealed containers at 2-25 C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 60 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. DO NOT STERILIZE. Cool to 45-50 C. Mix gently and dispense into sterile Petri dishes.


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. noculate plates with specimen and streak to obtain isolated colonies.
  2. Incubate at 35 C for 24 hours.
  3. Inoculate also a selective broth for better isolation.
  4. Examine for lactose non-fermenting colonies, with or without H2S.

QUALITY CONTROL
Results after 24 hrs at 35C

Organisms

ATCC

Growth

Salmonella typhimurium

14028

+ w/ H2S

Shigella flexneri

12022

+

Escherichia coli

25922

- or partial

Enterococcus faecalis

29212

- or partial


LIMITATIONS OF METHOD
It is recommended to inoculate specimens into some selective broth as enrichment to improve Salmonella and Shigella recovery. This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Ewing, E.H. 1976 Isolation and identification of Salmonella and Shigella. HEW Publication no. (CDC) 76-8098 Atlanta, Ga.
  2. Finegold, S.M., and W.J. Martin., 1984 Bailey's and Scott's Diagnostic Microbiology. 6th ed. St. Louis. The C.V. Mosby Company.
  3. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American Society for Microbiology.
  4. Mac Faddin, Jean F., Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria Vol.1 1985 Baltimore, MD. Williams & Wilkins.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-4206
     
Prepared media    
Plates, 100x15 mm 10/pkg 1127
Mono-Plates, 100x15 mm 10/pkg 1127M
     
Selective Enrichment Broth    
Selenite Broth, tube 16x125 mm 10/pkg 2815

 


 





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