|Staphylococcus aureus in Giolitti-Cantoni broth:
positive - left and negative - right
- G. Giolitti, C. Cantoni. A Medium for the Isolation of Staphylococci from Foodstuffs. J Appl Bacteriol. 1966 Aug;29(2):395-8.
- GIOLITTI-CANTONI Broth (Staphylococcus Enrichment Broth Base acc. to GIOLITTI and CANTONI). Merck Microbiology Manual
- GIOLITTI-CANTONI BROTH CM0523. Product leaflet, Oxoid.
- Giolitti Cantoni Broth Base M584I. Product leaflet, HiMedia.
Peptone from casein 10.0, meat extract 5.0, yeast extract 5.0, lithium chloride 5.0,
D(-)mannitol 20.0, sodium chloride 5.0, glycine 1.2, sodium pyruvate 3.0, Tween 80
Dispense 19 ml amounts into 20 x 200 mm test tubes and sterilise by autoclaving at
121 ºC for 15 minutes. Cool rapidly then aseptically add to each tube 0.1 ml of a 1 %
potassium tellurite solution.
Inoculate 1 gram of sample or 1 ml of a suitable dilution of a sample into 19 ml of
Giolitti-Cantoni Broth tubes. Overlay the medium with 5 ml molten sterile paraffin wax
and incubate at 37 ºC for 24-48 hours and examine daily.
RESULTS & INTERPRETATION
Blackening of the medium (starting from the bottom) within 48 hours indicates the
presence of Staphylococcus aureus. If blackening does occur, the broth is streaked
on to a staphylococcal isolation medium, such as Baird-Parker agar and incubated at
35 ºC for 24-48 hours. The result is considered positive if black colonies, with a
narrow white margin, surrounded by a clear zone, are produced.
S. aureus should be confirmed by coagulase test.
Staphylococcus aureus ATCC25923 - luxuriant growth, blackening of the medium;
Escherichia coli ATCC 25922 - inhibited, no blackening;
Micrococcus luteus ATCC 10240 - inhibited, no blackening.
A liquid selective enrichment medium for the isolation of staphylococci from foodstuffs (usually milk, meat and meat products). The
growth of staphylococci is promoted by pyruvate, glycine and above all by a high concentration of mannitol. Gram-negative
microorganisms are inhibited by lithium chloride while Gram-positives are inhibited by tellurite. Micrococci are inhibited by incubating
in anaerobic conditions or by overlaying with sterile paraffin wax.
|Giolitti - Cantoni Broth
Giolitti and Cantoni 1966
(c) Costin Stoica