What is the preferred medium for the culture of most Haemophilus?

Enriched chocolate agar is the preferred medium for the culture of most Haemophilus species because it provides the necessary nutrients and growth factors that these bacteria require. Haemophilus species are fastidious organisms; they need specific factors such as hemin (X factor) and nicotinamide adenine dinucleotide (V factor) for growth, which are present in the enriched chocolate agar but not in standard media like nutrient agar or tryptic soy agar.

In chocolate agar, the red blood cells are lysed during the preparation process, releasing these vital factors into the medium. This makes it an ideal environment for Haemophilus species to thrive and be isolated for further identification, as they cannot grow on simpler media that do not contain these essential growth factors. Bordet-Gengou agar, while useful for culturing Bordetella pertussis, does not support the growth of Haemophilus species, which is why it is not preferred for this purpose.