Description

Use and description:

Medium for primary differentiation and identification of the most common pathogens causing urinary tract infection diseases. The medium uses different substrates for the specific enzyme activity. The medium also support the growth of gram positive organisms like staphylococcus and enterococcus.

 

Composition per litre:

Chromogenic mix…………………0.28 g

Agar ATF.………………………………12.5g

Peptones………………………………10.0g

Meat extract………………….………1.5 g

Yeast extract…………………………9.0 g

IPTG…………………………………….…0.5g

PNPG……………………………. …..0.013g

Sodium Pyruvate…………..……….1.5g

L-Tryptophan………………….……..2.0g

 

Final pH of the ready to use medium: 6.7 ± 0.2

 

Medium preparation:

Add 37.28 grams of dehydrated culture medium to 1 litre of distilled water. Mix thoroughly. Heat with frequent agitation and boil for 1 min to dissolve completely. Autoclave for 15 min at 121°C. Cool to 45-50°C and pour into sterile petri dishes.

 

Quality specifications:

Dehydrated medium: homogeneous, straw coloured, fine powder.

Ready to use medium: Clear, amber agar

 

Microbiological response: 

OrganismResultColony appearance
E. coli ATCC 2522Growthpurple
Enterobacter aerogenes ATCC13048Growthdeep blue
Klebsiella spp. HNCMB52047Growthlight metallic blue
Enterococcus faecalis ATCC29212Growthlight blue
Proteus vulgaris ATCC8427Growthturquoise with gold halo
Proteus mirabilis ATCC12453Growthwhite with gold halo
Staphylococcus aureus ATCC 25923Growthwhite or yellow (depending on pigment production)
Streptococcus agalactiae ATCCGrowthlight grey

 

Storage:

Dehydrated medium should be stored between 10 to 25°C. Once opened, place the container in a dark, dry place. The dehydrated medium should not be used if there is any lump or the colour has changed from the original.