|Thyoglicolate broth with red oxygen indicator ring
Regenerate tubes on water at 100 ºC, cool fast then inoculate culture using a pipette
and starting from the bottom of the tube to the surface. Incubate at 37 ºC, up to 2 weeks.
RESULTS & INTERPRETATION
Anaerobes produce turbidity in the medium, mainly in the lower part, aerobes grow
close to the surface and microaerophilics prefer middle part of the tube.
Glucose, pancreatic digest of casein, and L-cystine are the growth factors. L-cystine
and sodium thioglycollate allows anaerobic microorganisms to grow in this medium
even under aerobic conditions. Also, the small amount of agar used in the medium
favors the growth of aerobes as well as anaerobes in the medium, even if sodium thioglycollate is deleted from the medium. Sodium
thioglycollate act as a reducing agent and neutralizes the toxic effects of preservatives and peroxides formed in the medium. The
oxygen content is indicated by resazurin.
Clostridium perfringens ATCC 13124 - luxuriant growth,
Staphylococcus aureus ATCC25923 - luxuriant growth,
Pseudomonas aeruginosa ATCC 27853 - luxuriant growth,
Escherichia coli ATCC 25922 - luxuriant growth,
- Handbook Culture Media Merck, 1982.
- Alexandru Rafila: Medii de cultura, medii de transport si conservare. In Dumitru Buiuc, Marian Negut: Tratat de microbiologie
clinica ed. III, 2009, 1045-1084.
Proteose peptone 10.0 g, meat infusion 5.0 g, D(+) glucose 5.0 g, K2HPO4 2.0 g,
sodium thioglycollate 0.5 g, methylene blue 0.002 g, agar-agar 0.5 g.
Distilled water ad 1000 ml, pH 7.0 ± 0.1, Pour in tubes and autoclave.
Clear, colorless & semi-solid state. Store in the dark, at room temperature.
Do not use green-blue tubes if color do not disappear after boiling.
VARIANT 2 - for fastidious anaerobes
Casein pancreatic digest 17.0 g, soy pancreatic digest 3.0 g, NaCl 2.5 g, glucose 6.0
g, sodium sulfite 0.1 g, sodium thioglycollate 0.5 g, resazurin sodium 0.001 g, agar
0.7 g, L-cystine 0.25 g, hemin 0.005 g.
Distilled water ad 1000 ml, pH 7.2, Pour in tubes. Do not boil, do not autoclave.
Supplement with 0.1 ml vitamin K1 1% solution dilluted 1/500 in distilled water and
0.2 ml Na2CO3 10% solution.
Medium for the cultivation of anerobic, microaerophilic & facultatively anaerobic germs. It may also be used for testing the
microorganisms' oxygen requirements, sterility testing of antibiotics, biologicals and foods and for determining the phenol coefficient
and sporicidal effect of disinfectants. Thioglycollate broth contains sodium thioglycollate, a reducing agent that creates anaerobic
conditions when it reduces molecular oxygen to water. Resazurin or methylene blue are usually added to the broth to provide a visual
indication of the presence of oxygen. Resazurin turns pink-red when oxidized (colorless when reduced). Methylene blue turns blue
when oxidized (colorless when reduced). Because thioglycollate tubes have an oxygen gradient, the location of growth in a tube
indicates the oxygen requirement of an organism.
(c) Costin Stoica