Which medium is preferred for the culture of Haemophilus species?

Enriched chocolate agar is preferred for the culture of Haemophilus species due to its rich nutrient composition, which supports the growth of these bacteria that require specific growth factors. Haemophilus species, particularly Haemophilus influenzae, are fastidious organisms that have complex nutritional requirements. They often need factors such as hemin (X factor) and nicotinamide adenine dinucleotide (V factor) to thrive, both of which are present in chocolate agar as a result of the lysis of red blood cells during the preparation of the medium.

In contrast, other types of media listed do not provide the necessary growth factors for these fastidious organisms. For instance, MacConkey agar is selective for gram-negative bacteria and contains bile salts and crystal violet, which inhibit the growth of gram-positive bacteria. Nutrient agar is a general-purpose medium that may not be sufficient for Haemophilus due to its lack of specific growth factors. Tryptic Soy Agar (TSA) plates, while more nutrient-rich than basic nutrient agar, still do not offer the specific enrichment necessary for culturing Haemophilus species effectively. Thus, enriched chocolate agar stands out as the most suitable medium for isolating and cultivating Haemophilus