Amphotericin B Resistant Aspergillus spp.: Report of Two Cases

Aspergillus spp. are ubiquitous, and people are frequently exposed to their spores in the environment and hospital settings. Despite frequent inhalation of the spores, Aspergillus infection is infrequent in humans, except in immunosuppressed hosts. Although amphotericin B (AmB) has been a first-line antifungal for invasive Aspergillus infections for 50 years, its success rate in these patients remains unsatisfactory. Resistance to AmB is sporadic, but the fungus can acquire resistance. Herein, we report two patients unresponsive to AmB, and eventually, we found that the fungi were resistant to AmB. The Aspergillus flavus species complex was recovered from endotracheal aspirate in one case. In the other case, the Aspergillus fumigatus species complex was recovered from a skin biopsy on liposomal amphotericin B (L-AmB) treatment. We used conventional methods for both Aspergillus spp. Initially, serum galactomannan tests were negative in the patients. The radiological results of two patients were compatible with invasive pulmonary aspergillosis, and later, the serum galactomannan levels in the cases increased rapidly during routine blood screening. Eventually, both patients died in intensive care.