Which is a common isolation medium for Actinobacillus spp.?

The correct answer is chocolate agar, which is a common isolation medium for Actinobacillus spp. This medium is enriched and allows for the growth of fastidious organisms, which may require additional growth factors that are not provided in simpler media. Chocolate agar is prepared by heating blood agar plates, which lyse the red blood cells and release nutrients such as hemoglobin, hemin, and other growth factors into the agar. This process promotes the growth of microorganisms that have specific nutrient requirements, such as Actinobacillus species.

Blood agar can also support the growth of various bacteria, but it is less effective for organisms with higher nutritional needs compared to chocolate agar. MacConkey agar is selective for Gram-negative bacteria and inhibits the growth of Gram-positive bacteria, making it unsuitable for growing Actinobacillus spp., which are Gram-negative but not strictly lactose fermenters. XLD (Xylose Lysine Deoxycholate) agar is primarily used for the isolation and differentiation of enteric Gram-negative bacteria, particularly those involved in gastrointestinal infections, and is not ideal for cultivating Actinobacillus species. Hence, chocolate agar is the most suitable medium for isolating Actinobacillus spp. due to its nutrient richness and