Multilocus Sequence Analysis of Aspergillus Species from Clinical Samples and the Surge of Cryptic Aspergillosis in Southern India: A Descriptive Cross-sectional Study

Autor: Almas Fathima Upaisal, Anupma Jyoti Kindo, Prasanna Kumar Saravanam, MA Thirunarayan, Lakshmi Sree
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Journal of Clinical and Diagnostic Research, Vol 18, Iss 10, Pp 04-09 (2024)
Druh dokumentu: article
ISSN: 2249-782X
0973-709X
DOI: 10.7860/JCDR/2024/72709.20211
Popis: Introduction: Aspergillus species cause a broad range of infections, from Allergic Bronchopulmonary Aspergillosis (ABPA) to invasive aspergillosis. Accurate species-level identification is crucial for diagnosis and treatment, especially since some rare Aspergillus species exhibit increased resistance to common antifungal agents. Aim: To identify Aspergillus species at the species complex level and determine the emergence of cryptic Aspergillus species using Multilocus Sequence Analysis (MLSA). Materials and Methods: This descriptive cross-sectional study was conducted over eight months, from January 2023 to August 2023, in three tertiary care centres in Chennai, India. Sixty Aspergillus strains were isolated from various clinical samples. The primary inclusion criteria were patients with suspected aspergillosis, categorised based on the European Organszation for Research and Treatment of Cancer Mycoses Study Group (EORTC-MSG) criteria. Isolates were grown on Oatmeal Agar or Sabouraud Dextrose Agar (SDA) and phenotypically identified using tease mount and slide culture techniques. Genomic fungal Deoxyribonucleic acid (DNA) was extracted and amplified using specific primers for Internal transcribed spacer (ITS), beta-tubulin, hydrophobin, and calmodulin genes, followed by nucleic acid sequencing. Results: Among the 60 Aspergillus isolates, the Aspergillus flavus complex comprised 26 (43.3%), the Aspergillus fumigatus complex 16 (26.7%), the Aspergillus niger complex 12 (20%), and the Aspergillus terreus complex 6 (10%). Initial speciation relied on microscopic and cultural characteristics. Isolates were recovered from various clinical specimens: bronchial wash 6 (10%), Bronchoalveolar lavage (BAL) fluid 10 (16.7%), sputum 3 (5%), ear swab 20 (33.3%), endotracheal aspirate 8 (13.3%), pus and tissue from the nasal cavity and paranasal sinus 11 (18.3%), and tissue from other sites 2 (3.3%). MLSA identified common species such as A. flavus, A. fumigatus, A. terreus, and A. niger, as well as rare species including A. awamori, A. carneus, A. lentulus, A. oryzae, A. tamarii, A. tubingensis, and A. welwitschiae. Sequence identity ranged from 99% to 100%, confirming species diversity. Phylogenetic analysis using ITS, beta-tubulin, hydrophobin, and calmodulin genes supported species identification with robust bootstrap support (1000 replications). Conclusion: Cryptic Aspergillus species are prevalent in clinical samples from the South Indian population, with a notable presence from the section Nigri and the first-time isolation of Aspergillus carneus in clinical samples from India. Molecular identification is essential for determining the invasive potential and guiding appropriate antifungal therapy
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