EMD Cat. No. 1.01347.0500 |
500 g |
Selective agar proposed by HOLT-HARRIS and TEAGUE (1916) for the detection and isolation of pathogenic Enterobacteriaceae. |
Mode of Action | Preparation |
Experimental Procedure and Evaluation | Quality Control |
Typical Composition (g/liter) | Literature |
Picture/Image |
Mode of Action The lactose and sucrose contained in this medium allow lactose- and sucrose-negative salmonellae and shigellae to be distinguished from lactose-positive coliform organisms and lactose-negative, sucrose-positive, accompanying flora (e.g. Proteus vulgaris, Citrobacter, Aeromonas hydrophila). The growth of undesired accompanying microorganisms, particularly Gram-positive bacteria, is largely inhibited by the dyes present in the medium.
Typical Composition (g/liter) Peptones 10.0; di-potassium hydrogen phosphate 2.0; lactose 5.0; sucrose 5.0; eosin Y, yellowish 0.4; methylene blue 0.07; agar-agar 13.5.
Preparation Suspend 36 g in 1 liter of purified water. Autoclave (15 min at 121°C), pour plates. pH: 7.1 ± 0.2 at 25°C. The plates are clear and reddish-brown to violet-brown.
Experimental Procedure and Evaluation Inoculate by spreading the sample material thinly on the surface of the plates. Incubation: 24 hours at 35°C aerobically.
Appearance of Colonies | Microorganisms |
Translucent, amber colored | Salmonella, Shigella |
Greenish, metallic sheen in reflected light, blue-black centre in transmitted light | Escherichia coli |
Colonies are larger than those of E. coli, mucoid, confluent, gray-brown centre in transmitted light | Enterobacter, Klebsiella and others |
Quality control |
Test strains | Growth | Colony color | Metallic sheen |
Escherichia coli ATCC 25922 | good / very good | violet | + |
Escherichia coli ATC 11775 | good / very good | violet | + |
Escherichia coli 194 | good / very good | violet | + |
Escherichia coli ATCC 23716 | good / very good | violet | + |
Escherichia coli ATCC 8739 | good / very good | violet | + |
Enterobacter cloacae ATCC 13047 | fair / very good | pink, dark centre | + / - |
Salmonella typhimurium ATCC 14028 | good / very good | colorless, transparent | - |
Shigella flexneri ATCC 12022 | good / very good | colorless, transparent | - |
Bacillus cereus ATCC 11778 | none / poor | | - |
Literature |
HOLT-HARRIS, J.E., a. TEAGUE, O.A.: A new culture medium for the isolation of Bacillus typhosus from stools. - J. Infect. Dis., 18; 596-600 (1916).
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