Why is therapy of blastomycosis so long and expensive? Why not just give the dog or person common antibiotics?
Blastomyces dermatitidisis a fungus. Fungi have morphological and biochemical characteristics that are far different from the bacteria against which common antibiotics have been devised. Thus, these drugs are ineffective and cannot be used to treat blastomycosis or other fungal infections. In fact, the yeast of Blastomyces dermatitidis bears some biochemical resemblance to the cells of mammals themselves. Thus, one has to be careful in terms of devising drugs to attack these fungi, since some of these might also recognize and have adverse effects on cells of the host. This is best exemplified by the antifungal drug Amphotericin-B, which binds to ergosterol in the fungal membrane, but also binds somewhat to cholesterol in mammalian membranes. As a result, it commonly causes renal toxicity when it is used therapeutically. There are a limited number of antifungal drugs that are effective against systemic fungal pathogens such as Blastomyces dermatitidis. These fall largely into two classe
