TTC CHAPMAN AGAR (Lactose Agar TTC with Tergitol 7)
CAT Nº: 1076
For the detection and enumeration of E.coli and coliforms in
drinking water by membrane filtration technique
FORMULA IN g/l
Lactose
20.00 Sodium Heptadecyl Sulfate (Tergitol 7)
Peptone
10.00 Bromothymol Blue
Yeast Extract
6.00 Bacteriological Agar
Beef Extract
5.00
0.10
0.050
15.00
Final pH 7.2 ± 0.1 at 25ºC
Non fermenting species
PREPARATION
Escherichia coli
ATCC 25922
Suspend 56.15 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent
agitation. Boil for one minute until complete dissolution. Sterilize in autoclave at 121ºC for 15 minutes. Cool to 45-50ºC
and aseptically add 2.5 ml of TTC 1% Supplement (Cat. 6030) previously reconstituted in 5 ml of sterile distilled water.
Homogenize gently and dispense into Petri dishes. DO NOT OVERHEAT THE MEDIUM. The prepared medium should be
stored at 2-8°C. The color is green.
The dehydrated medium should be homogeneous, free-flowing and greenish-beige in color. If there are any physical
changes, discard the medium
TTC 1% SUPPLEMENT (CAT. 6030)
1 Vial reconstructed in 5 ml of distilled water
Triphenyltetrazolium Chloride ……………………………
50 mg
USES
TTC CHAPMAN AGAR (Lactose Agar TTC with Tergitol 7) is a selective and differential medium prepared according to
ISO 9308-1, is used for the presumptive control of E.coli and coliforms in waters for human consumption by the
membrane - filtration technique.
Peptone and Beef extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is
source of vitamins, particularly the B-group. Lactose is a fermentable carbohydrate providing carbon and energy. Sodium
heptadecylsulfate (Tergitol 7) and TTC inhibit most gram positive bacteria. Bromothymol blue is a pH indicator.
Bacteriological agar is the solidifying agent.
The norm ISO 9308-1 recommends:
Two samples of water must be taken on two membranes and incubated in TTC Chapman Agar at 36±2°C and
44 ±4 °C respectively. After 21 ± 3 hours of incubation:
- E. coli and Citrobacter spp present yellow colonies with orange-colored center.
- Enterobacter spp form red colored colonies and dark yellow with orange-colored center. The medium is yellow.
- Klebsiella spp form red colored or yellow, but without center. The medium is yellow.
- Lactose non fermentative bacteria grow with purple colonies and change the medium to blue.
1
LABORATORIOS CONDA, S.A.
www.condalab.com
- Klebsiella and Enterobacter species can also produce yellow-green colonies.
The results will always refer to counts per 100 ml of sample (considering if it has been necessary to make dilutions). The
colonies that grow at 36±2°C will be considered as fecal coliforms and the colonies that grow at 44 ±4°C are considered
as E. coli.
Confirmation of the colonies in EMB Agar (Cat. 1039), Kligler Iron Agar (Cat. 1042), etc. is necessary for the verification
of the biochemical characteristics. The Indole and Oxidase tests are carried out in the following media respectively:
Tryptophan Culture Broth (Cat. 1237) and Tryptone Soy Agar (Cat. 1138).
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures, with the Supplement added,
after incubation at a temperature of 36± 2°C and observed after 21± 3 hours.
According to ISO 11133 (21±3h/) 36±2ºC) Productivity, Selectivity and Specificity
Microorganisms
Escherichia coli ATCC
25922
Escherichia coli ATCC
8739
Enterococcus faecalis
ATCC 19433
Pseudomonas
aeruginosa ATCC 27853
Inoculum
(cfu/ml)
Reference
media (cfu)
Media test Productivity
(cfu)
Quantitative
Characteristic
Reaction
Specificity
Qualitative
102
PR≥70%
yellow in the central
part below the
membrane
102
PR≥70%
yellow in the central
part below the
membrane
Selectivity
Qualitative
Inhibited
Total
10 4/ 106
colonies red with blue in
the center
103/104
BIBLIOGRAPHY
Chapman G.H. 1946. A single culture medium for selective isolation of plasma coagulating staphylococci and for improved testing of
chromogenesis (J. Bacteriol. 51: 409-410).
Tittsler R.P. and L.A. Sandholzer. 1936. The Use of Semi-Solid Agar for the detection of bacteria motility. (J. Bacteriol 31: 575-580)
ISO 9308-1.Water quality. Detection and enumeration of Escherichia coli and coliform bacteria.PART.1. Membrane filtration method
ISO
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com