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Difco Tinsdale Enrichment Desiccated is used with Difco Tinsdale Agar Base for primary isolation and differentiation of Corynebacterium diphtheriae.

Tinsdale Agar Base, supplemented with Tinsdale Enrichment, is employed in the cultural diagnosis of diphtheria. Diphtheria, an acute infectious disease primarily of the upper respiratory tract but occasionally of the skin,¹ is caused by toxigenic strains of Corynebacterium diphtheriae. The three biotypes are mitis, intermedius and gravis.¹ The signs and symptoms of the disease are a pharyngeal membrane, sore throat, malaise, headache and nausea.² Death can result from respiratory obstruction by the membrane or myocarditis caused by the toxin.²

Tinsdale³ developed a serum-cystine-thiosulfite-tellurite agar medium for the primary isolation and differentiation of C. diphtheriae. This formulation distinguished between C. diphtheriae and diphtheroids which exhibited similar characteristics. The differential principle is based on the capacity of C. diphtheriae to produce a brown or black halo around the colonies.

Billings⁴ simplified Tinsdale Basal Medium by using Proteose Peptone No. 3 as a nutrient source. This modification improved the differential qualities and recovery of C. diphtheriae. Moore and Parsons⁵ confirmed the halo formation of C. diphtheriae with one exception; C. ulcerans occasionally produced colonies similar to C. diphtheriae and required biochemical identification.

Prepare Tinsdale Agar per label directions. Inoculate to obtain discrete colonies and stab several times using an inoculating needle; incubate at 35 ± 2°C for 18–48 h.

For Laboratory Use.

Observe aseptic techniques and established precautions against microbiological hazards throughout all procedures. After use, prepared plates, specimen containers and other contaminated materials must be sterilized by autoclaving before discarding.