Molecular identification, phylogenetic analysis and antifungal susceptibility patterns of Aspergillusnidulans complex and Aspergillusterreus complex isolated from clinical specimens.

OBJECTIVE: Aspergillus sections Terrei and Nidulantes are the less common causes of invasive aspergillosis and pulmonary aspergillosis (PA) in immunocompromised patients when compared to A. fumigatus and A. flavus. Identifying these fungi as the infectious agent is crucial because of the resistance to amphotericin B (AMB) and increased lethality. The aim of this study was to identify the molecular status, evaluate the genetic diversity and examine the antifungal susceptibility profile of the uncommon Aspergillus species. Forty-five uncommon Aspergillus species were identified based on the microscopic and macroscopic criteria. Then, the molecular identification was performed using the sequencing beta tubulin (benA) gene. In vitro antifungal susceptibility to amphotericin B (AMB), itraconazole (ITC), ravuconazole (RAV), voriconazole (VRC), caspofungin (CFG) isavuconazole (ISA) and posaconazole (POS) test was performed according to the CLSI M38-A2 guidelines. RESULTS: A. terreus was the most species detected, followed by A. nidulans, A. latus, A.ochraceus, and A. citrinoterreus, respectively. The analysis of the benA gene showed the presence of 12 distinct genotypes among the A. terreus isolates. The other species did not show any intraspecies variation. CFG exhibited the lowest MEC50/MIC50 (0.007µg/mL), followed by POS (0.125µg/mL), VRC, ITC, ISA (0.25µg/mL), RAV (0.5µg/mL), and AMB (8µg/mL). Among all the isolates, only 15.5% (7/45) were susceptible to AMB. CONCLUSION: Antifungal susceptibility pattern of the uncommon Aspergillus species is useful to improve patient management and increase knowledge concerning the local epidemiology. Moreover, this information is necessary when an outbreak dealing with drug-resistant infections occurs.

An unusual case of gastrointestinal basidiobolomycosis mimicking colon cancer; literature and review.

Gastrointestinal basidiobolomycosis (GIB), a rare fungal infection associated with high mortality, has been reported worldwide mainly from tropical and subtropical regions of Asia, USA, and Latin America. The clinical manifestations are highly diverse and non-specific depending on the underlying disease, but fever, abdominal pain, weight loss, diarrhea, constipation and chills have been observed. There are no prominent risk factors for GIB but climatic conditions and life style are related to this infection in arid and semi-arid regions. Therefore timely diagnosis and early treatment is a challenge. Herein, we present an unusual case of gastrointestinal basidiobolomycosis in a 54-year-old male, initially misdiagnosed as colon cancer. After follow-up, no evidence of relapse and the patient was successfully cured by liposomal amphotericin B. In addition, the differential diagnosis and histopathological findings are discussed with a review of the literature.

Pesticide behavior in paddy fields and development of azole-resistant Aspergillus fumigatus: Should we be concerned?

Tricyclazole as a common fungicide wildly used to control rice blast disease in the Asian country may induce azole resistance in Aspergillus fumigatus isolates. The main reason of the acquired azole resistance is probably environmental exposure through wide fungicide use in agriculture. The present study was conducted with the aim of investigating the current status of the azole-resistant A. fumigatus obtained from the paddy fields with exposure to tricyclazole. A total of 108 soil samples were collected from four different locations of paddy fields in Mazandaran Province, Iran. Pure fungal colonies were initially identified based on the conventional tools, and then reconfirmed by using DNA sequencing of the partial ß-tubulin gene. In addition, the in vitro antifungal susceptibility was determined using the Clinical and Laboratory Standards Institute document (CLSI) M38-A2. The identification of the mutations in the CYP51A gene was accomplished by the implementation of the polymerase chain reaction amplification assay on the selected isolates. Overall, 31 of 108 (28.7%) isolates were identified as A. fumigatus, four (3.7%) of which were recognized as azole-resistant with MICs of itraconazole ≥8µg/ml and voriconazole ≥4µg/ml. Only two out of the four azole-resistant A. fumigatus isolates harboured TR34/L98H variant and the other two isolates were identified as azole-resistant without any CYP51A gene mutations. However, other point mutations (TR46/Y121F/T289A) were not detected in the CYP51A gene. The high molecular structure similarity between environmental and medical triazoles may result in the selection of resistance mechanisms. Nonetheless, one might conclude that tricyclazole with different molecular structures against medical azoles induces azole-resistance in A. fumigatus isolates. The behavior of such pesticides as tricyclazole in the rice paddy fields would have an effective role in the development of azole-resistance that requires detailed information.