Investigation of the Relationships Between Clinical and Environmental Isolates of Aspergillus fumigatus by Multiple-locus Variable Number Tandem Repeat Analysis During Major Demolition Work in a French Hospital

Background. Genotyping is needed to explore the link between clinical cases from colonization of invasive aspergillosis (IA) and major building construction. Attempts to correlate Aspergillus fumigatus strains from clinical infection or colonization with those found in the environment remain controversial due to the lack of a large prospective study. Our aim in this study was to compare the genetic diversity of clinical and environmental A. fumigatus isolates during a demolition period. Methods. Fungal contamination was monitored daily for 11 months in 2015. Environmental surveillance was undertaken indoors and outdoors at 8 locations with automatic agar samplers. IA infection cases were investigated according to European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria. Isolates were identified by amplification and sequencing of the beta-tubulin gene. They were genotyped by multiple-locus variable number tandem repeat analysis (MLVA). The phylogenetic relationships between isolates were assessed by generating a minimum spanning tree. Results. Based on 3885 samples, 394 A. fumigatus isolates (383 environmental and 11 clinical) were identified and genotyped using MLVA. Clinical isolates were collected from patients diagnosed as having probable IA (n = 2), possible IA (n = 1), or bronchial colonization (n = 6). MLVA generated 234 genotypes. Seven clinical isolates shared genotypes identical to environmental isolates. Conclusions. Among the diversity of genotypes described, similar genotypes were found in clinical and environmental isolates, indicating that A. fumigatus infection and colonization may originate from hospital environments.