Isolate and differentiate Corynebacterium diphtheriae types with Thermo Scientific™ Oxoid™ Hoyle Medium Base (Dehydrated).
Hoyle medium is the well-known modification1 of Neill’s medium for the cultural isolation and differentiation of Corynebacterium diphtheriae types. Hoyle medium does not exert the inhibitory effect manifested by Neill’s on some mitis types, but gives very rapid growth with all types of Corynebacterium diphtheriae, so that diagnosis is possible after 18 hours’ incubation.
Corynebacterium diphtheriae is a rod-shaped, Gram positive, non-spore-forming, and nonmotile bacterium that causes diphtheria. Diphtheria can lead to difficulty breathing, heart failure, paralysis, and even death.
Hoyle Medium Base is a highly selective medium which is used in parallel with non-selective media such as blood agar. Unlike non-selective media, Hoyle medium should be inoculated by rubbing the throat swab (or other material) over the entire surface - spreading with a platinum loop is not necessary.
Colonial characteristics
Corynebacterium diphtheriae type gravis - grey colonies, 1.5-2.5mm diameter, dull, matte surface. May be slightly umbonate and show indented margins. Colonies can be pushed along the surface of the medium.
Corynebacterium diphtheriae type mitis - grey colonies, 1.5-2.0mm diameter with regular margins and shining surface. Variation in size common.
Corynebacterium diphtheriae type intermedius - grey colonies, 0.5-0.75mm diameter with shining surface. Colonies are very uniform in size with darker centers.
Corynebacterium hofmannii - usually rounded, white or greyish, 0.5-0.75mm diameter. Colonies may be up to 1mm diameter, when they are black in more heavily inoculated areas and white when well isolated.
Corynebacterium xerosis - black shining colonies of variable size.
Streptococci - minute black or brownish-black colonies
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Other organisms may occasionally grow which resemble Corynebacterium diphtheriae type intermedius but are larger, while sporing anaerobes may produce brownish mucoid colonies.
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Code | Description |
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CM0083B | Catalog Number: CM0083B Unit Size: Each Quantity: 500 g |