Thermo Scientific™ Porphyrin Test Agar

Description

• Speciate the genus Haemophilus based on their ability to convert delta-aminolevulinic acid (ALA) to porphyrins with Thermo Scientific™ Remel™ Porphyrin Test Agar
• White and Granick found H
• influenzae , H
• aegyptius and H
• haemoglobinophilus lack the enzyme to convert ALA to protoporphyrin which accounts for their dependence on hemin (X factor) for growth 1
• In 1986, Gadberry et al
• compared Porphyrin Test Agar (PTA) with conventional paper strip satellite method 2 and found PTA to be considerably an easier method
• Porphyrin Test Agar is a solid medium that is used for speciation of Haemophilus based on the ability to convert delta-aminolevulinic acid (ALA) to porphyrin
• Porphyrin Test Agar contains hemoglobin as a source of hemin
• Porphyrin Test Agar contains GCHI enrichment, a defined supplement which provide NAD, vitamins, amino acids, coenzymes, dextrose, and other nutrients necessary for the growth of Haemophilus spp
• This medium provides an accurate means to determine X factor requirement based on the observation that X-independent Haemophilus strains excrete porphobilinogen and porphyrins, all of which are intermediates in the hemin biosynthetic pathway when supplied with ALA
• After incubation there is a color change in the colonies in presence of longwave ultraviolet light.