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m - AEROMONAS SELECTIVE AGAR BASE

 

Base medium for the isolation of Aeromonas spp.o:p>

 

Code: CB1/3191

 

Typical formula  g/l

 

Tryptose 5.00
Yeast extract 2.00
Dextrin 11.40
Sodium chloride 3.00
Potassium chloride 2.00
Magnesium sulphate 0.10
Ferric chloride 0.06
Sodium desoxycholate 0.10
Bromothymol blue   0.08
Agar 13.00

 

          

+ Aeromonas Selective Supplement (vial contents for 500 ml of medium) Ampicillin 5 mg

 

Final pH: 8.0 +/- 0.2

 

Directions

Suspend 18.35 g of m-Aeromonas Selective Agar Base in 500 ml of cold distilled water. Heat to boiling with frequent agitation and sterilise by autoclaving at 121°C for 15 minutes. Cool to approximately 50°C and, under aseptic conditions, add the contents of one vial of Aeromonas Se­lective Supplement-Ampicillin reconstituted with 5ml of sterile distilled water. Mix well and distribute Aeromonas Selective Agar into sterile 55mm dishes.

 

Description

The significance of Aeromonas species as human pathogens is getting increasing attention (Holmberg and Farmer); many inve­stigators have reported that the aquatic environment can be con­sidered the biggest source of infection, Buchanan and Palumbo implicated Aermonas as potential food-poisoning agent.

 

m-Aeromonas Selective Agar Base is used for the detection of Aeromonas in water and other liquid samples by means of a membrane filtration procedure. Appropriate volumes or decimal dilutions of the samples are filtered using membrane filters 0.45μm pore size, and the filters are tran­sferred onto the plates.

After 24 hours of incubation at 30°C in aerobic conditions, Aero­monas colonies show a visible yellow colour (dextrin fer­mentation). The detection of dextrin fermentation is considered to be highly specific and until now no dextrin negati­ve Aeromonas strains have been found.

Confirm the presumptive detection with standard biochemical tests. The use of ampicillin suppresses adequately the background flora without having any decrease in the Aeromonas recovery. Strains sensitive to 10 mg/l of ampicillin appear to occur at a fre­quency of 1% or less.

 

User quality assurance   (30°C-24 h)

Productivity control

A.hydrophila ATCC 7965: good growth

Selectivity control

E.coli ATCC 25922: inhibited

 

Storage

Dehydrated media: 15-30°C

User prepared plates: up to 7 days at 2-8°C

 

References  

•  Buchanan, R.L., Palumbo, S.A. (1985) J. Food  Saf. 7, 15-29

•  Palumbo, S.A. et al. (1985) App. Environ. Microbiol. 50, 1027- 1030 

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