Identification by Molecular Methods and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Antifungal Susceptibility Profiles of Clinically Significant Rare Aspergillus Species in a Referral Chest Hospital in Delhi, India

Aspergillus species cause a wide spectrum of clinical infections. AlthoughAspergillus fumigatus andAspergillus flavus remain the most commonly isolated species in aspergillosis, in the last decade, rare and crypticAspergillus species have emerged in diverse clinical settings. The present study analyzed the distribution andin vitro antifungal susceptibility profiles of rareAspergillus species in clinical samples from patients with suspected aspergillosis in 8 medical centers in India. Further, a matrix-assisted laser desorption ionization–time of flight mass spectrometry in-house database was developed to identify these clinically relevantAspergillus species. β-Tubulin and calmodulin gene sequencing identified 45 rareAspergillus isolates to the species level, except for a solitary isolate. They included 23 less commonAspergillus species belonging to 12 sections, mainly inCircumdati ,Nidulantes ,Flavi ,Terrei ,Versicolores ,Aspergillus , andNigri . Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identified only 8 (38%) of the 23 rareAspergillus isolates to the species level. Following the creation of an in-house database with the remaining 14 species not available in the Bruker database, the MALDI-TOF MS identification rate increased to 95%. Overall, high MICs of ≥2 μg/ml were noted for amphotericin B in 29% of the rareAspergillus species, followed by voriconazole in 20% and isavuconazole in 7%, whereas MICs of >0.5 μg/ml for posaconazole were observed in 15% of the isolates. Regarding the clinical diagnoses in 45 patients with positive rareAspergillus species cultures, 19 (42%) were regarded to represent colonization. In the remaining 26 patients, rareAspergillus species were the etiologic agent of invasive, chronic, and allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, keratitis, and mycetoma.