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DIATABS ™
05-2007 Ch. 3
Page 29 of 130
3.5
ARGININE DIHYDROLASE (ADH)
REF No. 56211
L-arginine is broken down in a two step process: first from l-arginine to l-citrulline (ADH) followed by a citrulline
splitting system. The over-all reaction results in the formation of l-ornithine, CO2 and NH3 from the substrate l-arginine,
resulting in an alcalinization of the medium and a change of colour of the indicator from yellow to red.
Procedure
Prepare a dense “milky” suspension (at least McFarland No. 4) from the strain to be tested in 0.25 ml saline in a tube.
Add one ADH Diagnostic Tablet and 3 drops of sterile paraffin oil. Close the tube and incubate at 35-37 °C for
4 hours or up to 18-24 hours.
Reading of the test
Positive reaction:
Negative reaction:
Red
Yellow
After overnight incubation, positive reaction: strong red; negative reaction: yellow or orange. In most cases overnight
incubation is necessary.
Results
1) Enterobacter
Positive:
Usually negative:
Enterobacter cloacae
Other Enterobacter spp.
ADH
97
0
0
99
0
E. cloacae
E. aerogenes
E. intermedium
E. sakazakii
E. agglomerans
MR
5
5
100
5
50
Remarks
α-GLU +
ODC 0
ADH = Arginine Dihydrolase D.T., MR = Methyl Red, α-GLU = Alpha-Glucosidase D.T., ODC = Ornithine
Decarboxylase D.T.
2) Streptococci/Enterococci
Positive:
Negative:
E. faecalis, E. faecium, E. durans, E. gallinarum, E. casseliflavus.
Group D streptococci (Strept. bovis, Strept. equinus) E. avium, E. raffinosus.
3) Non-fermenters
Positive:
Negative:
Ps. aeruginosa, Ps. fluorescens, Ps. putida, Ps. pseudoalcaligenes, Ps. alcaligenes, Ps. stutzeri,
Cryseom. luteola (Ve-1).
St. maltophilia, Sphing. paucimobilis, Shew. putrefaciens, Flavobacterium spp.,
Brev. vesicularis, Com. acidovorans, Com. testosteroni, Pasteurella multocida, Ralst. pickettii,
Alcaligenes spp., Brev. diminuta, Burkh. cepacia, Oligella spp.
4) Staphylococci
Usually positive:
Usually negative:
S. aureus, S. haemolyticus, S. schleiferi, S. simulans, S. warneri, S. capitis.
S. hominis, S. lugdunensis, S. saprophyticus, S. xylosus, S. cohnii, S. sciuri, S. lentus
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