There are few reports on the clinical course of proven invasive aspergillosis (IA) due to rare/cryptic species in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. We retrospectively reviewed the electronic medical records of patients who underwent allo-HSCT between January 2012 and December 2018. Of 934 allo-HSCT recipients, 10 were diagnosed with proven IA and 61 were diagnosed with probable IA. DNA sequencing was performed in cases of proven IA, and
Aspergillus
could be identified to the species level in 8 of the 10 cases. Three were due to
A. fumigatus
, and 5 were due to rare/cryptic
Aspergillus
species, namely,
A. turcosus
,
A. felis
,
A. viridinutans
,
A. nidulans
, and
A. calidoustus
. In these 8 patients, no patients with IA due to
A. fumigatus
died, whereas 3 of the 5 with IA due to rare/cryptic species died within 12 weeks. The 2 surviving cases of IA due to rare/cryptic species were treated with surgical resection and antifungal treatment. Susceptibility testing for cryptic species in 4 cases showed an amphotericin B minimum inhibitory concentration (MIC) > 1 mg/L in 3 cases, itraconazole MIC > 1 mg/L in 2 cases, and voriconazole MIC > 1 mg/L in 2 cases. In conclusion, more than half of the causative pathogens of proven IA were rare/cryptic species, so it is important to accurately identify the
Aspergillus
species. In addition, surgical treatment might be an important option in cases of proven IA, given the possibility that the causative organisms are azole-resistant
A. fumigatus
or rare/cryptic species.
Persistent poor long-term prognosis of allogeneic hematopoietic stem cell transplant recipients surviving invasive aspergillosis
