- DHL Agar (Desoxycholate Hydrogen Sulfide de Lactose Agar) allows optimal growth of Shigella and Salmonella which do not grow well on SS Agar.

- It is also used for the isolation of pathogenic coli.

1. Preparation

- Add 63.3 g of dry medium to 1 L of distilled water, mix well and heat to dissolve.

- Distribute 20 mL per Petri dish and leave to solidify before use.

2. Identification

- Incubate at 37 °C for 20 hours. Avoid inoculating too much sample, approximately the same amount of sample used
for MacConkey Agar is recommended.

- Lactose, saccharose non-fermenting organisms form colorless transparent colonies relatively larger than those on SS Agar. Lactose, saccharose fermenting organisms form red opaque colonies. So, differentiation between the two organisms is simple.

- Organisms producing hydrogen sulfi de are liable to form black colonies.

2. Remark

Although this medium has low selectivity, it supports excellent growth of Shigella and Salmonella that do not grow well on SS Agar. It is also used for the isolation of pathogenic coli.

3. Formula

4. Information DHL Agar 05040