Species distribution and antifungal susceptibility patterns of Aspergillus isolates from clinical specimens and soil samples in Mexico

Abstract

Abstract This study aimed to assess the species distribution and antifungal susceptibility patterns of 200 strains of Aspergillus isolated from clinical specimens (n = 146) and soil samples (n = 54) in Mexico. ITS, β-tubulin, and calmodulin DNA sequencing was performed for species identification. Broth microdilution susceptibility testing for amphotericin B, voriconazole, posaconazole, itraconazole, isavuconazole, anidulafungin, caspofungin, and micafungin was done according to CLSI for all strains. A. fumigatus was most frequently recovered from clinical specimens, while A. niger was commonly encountered in soil, both followed by A. flavus in the second place. A total of 60 (30%) cryptic species were identified, with A. tubingensis and A. tamarii being the most commonly found. The decreased susceptibility to amphotericin B and azoles was 32% for both, and were mainly led by A. fumigatus, whereas this percentage decreased to 9% for caspofungin, particularly in A. terreus. More than 75% of cryptic species were susceptible in vitro to all antifungals. Multi-azole decreased susceptibility was detected only in seven isolates. Given that antifungal resistance in Aspergillus spp. is an increasing worldwide threat that causes major challenges in the clinical management of aspergillosis, these data highlight the need for continuous epidemiological surveillance of these pathogens for the implementation of locally adequate treatment strategies. Lay summary This is an epidemiological study in Mexico. A. fumigatus was most frequent in clinical specimens and A. niger in soil samples. A. tubingensis and A. tamarii were the most common cryptic species. Resistance to amphotericin B and azoles was 32% each, and 9% for caspofungin.