Citrate Utilization Test
DESCRIPTION
Testing the ability of bacteria to utilize sodium or ammonium citrate as sole carbon source. Simmons Citrate Agar medium is the
most used for Enterobacteriaceae identification, together with TSI and MIU media.
MEDIUM PREPARATION
Composition of Simmons medium:
Magnesium sulphate .........................................................................0.2g
Ammonium (or sodium) phosphate ..................................................1g
Disodic phosphate ...............................................................................1g
Sodium citrate .......................................................................................2g
NaCl ........................................................................................................5g
Bromtymol blue ...............................................................................0.08g
Agar ......................................................................................................15g
H
2O ad 1000 ml,  pH = 6.8

PROCEDURE
Pick a well isolated colony and disperse on medium surface. Incubate 24 hours
at 37 °C.
RESULTS
Reaction is positive if medium color turn from green to blue and negative if medium remains green.
REFERENCES:
1. H. Raducanescu, V.Bica-Popii,1986. Bacteriologie veterinara, Ed. Ceres, Bucuresti.
2. Margaret Barnett, 1992. Microbiology Laboratory Exercises. Wm. C. Brown Publishers.
Antibiogram
Encyclopedia
Culture media
Biochemical tests
Stainings
Images
Movies
Articles
Identification
Software
(c) Costin Stoica
A demonstration of TSI,MIU and Simmons utilization is available in video section.
R E G N U M
PROKARYOTAE
Previous page
Back