In-vitro antifungal susceptibility testing of lanoconazole and luliconazole against Aspergillus flavus as an important agent of invasive aspergillosis.

INTRODUCTION: The incidence of Aspergillus infections has recently increased remarkably in certain tropical and sub-tropical countries, with Aspergillus flavus being identified as the leading cause of infections after A. fumigatus. Lanoconazole (LAN) and luliconazole (LUL) are currently approved for topical treatment of cutaneous fungal infections. We aimed the in-vitro antifungal susceptibility testing of two imidazole, LAN and LUL against A. flavus. METHODS: One hundred and eighty-seven clinical and environmental A. flavus were tested originating from different climate zones of Iran between 2008 and 2015. The identification of all isolates was confirmed by using PCR-sequencing of ß-tubuline ribosomal DNA gene. In-vitro antifungal susceptibility test was performed using CLSI guidelines against LAN, LUL, itraconazole (ITC), voriconazole (VRC), posaconazole (POS), Isavuconazole (ISA), amphotericin B (AMB), 5-flucytosine (5FC), caspofungin (CAS) and anidulafungin (AFG). The minimum inhibitory concentration (MIC) and minimum effect concentration (MEC) values were evaluated according to CLSI M38-A2 guidelines. RESULTS: The geometric mean MICs for tested antifungals, in increasing order, were: 0.009 µg/mL for LUL (ranging from 0.004 to 0.062), 0.02 µg/mL for LAN (ranging from 0.004 to 0.125), POS (0.10), ISA (0.16), ITC (0.24), VRC (0.27), AMB (1.8) and 5FC (63.06) µg/mL. The mean value of MECs for AFG and CAS were 0.06 and 0.07, respectively. CONCLUSION: Overall, LUL and LAN showed the lowest MIC against all isolates of A. flavus. Further studies are required to evaluate the in-vivo efficacy of these agents, and the possibility of using these agents in systemic infections.

Genetic Diversity and In Vitro Antifungal Susceptibility of 200 Clinical and Environmental Aspergillus flavus Isolates.

Aspergillus flavus has been frequently reported as the leading cause of invasive aspergillosis in certain tropical and subtropical countries. Two hundred A. flavus strains originating from clinical and environmental sources and collected between 2008 and 2015 were phylogenetically identified at the species level by analyzing partial ß-tubulin and calmodulin genes. In vitro antifungal susceptibility testing was performed against antifungals using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. In addition, genotyping was performed using a short-tandem-repeat (STR) assay of a panel of six microsatellite markers (A. flavus 2A, 2B, 2C, 3A, 3B, and 3C), in order to determine the genetic variation and the potential relationship between clinical and environmental isolates. The geometric means of the minimum inhibitory concentrations/minimum effective concentrations (MICs/MECs) of the antifungals across all isolates were (in increasing order): posaconazole, 0.13 mg/liter; anidulafungin, 0.16 mg/liter; itraconazole, 0.29 mg/liter; caspofungin, 0.42 mg/liter; voriconazole, 0.64 mg/liter; isavuconazole, 1.10 mg/liter; amphotericin B, 3.35 mg/liter; and flucytosine, 62.97 mg/liter. All of the clinical isolates were genetically different. However, an identical microsatellite genotype was found between a clinical isolate and two environmental strains. In conclusion, posaconazole and anidulafungin showed the greatest in vitro activity among systemic azoles and echinocandins, respectively. However, the majority of the A. flavus isolates showed reduced susceptibility to amphotericin B. Antifungal susceptibility of A. flavus was not linked with the clinical or environmental source of isolation. Microsatellite genotyping may suggest an association between clinical and environmental strains, although this requires further investigation.

Invasive aspergillosis in intensive care unit patients in Iran.

We assessed the intensive care unit (ICU) patients for Invasive aspergillosis (IA) with culture and non-culture based diagnostic methods from Iran. Thirty-six ICU patients with underlying predisposing conditions for IA were enrolled in the study. Sixty eight Bronchoalveolar lavage (BAL) samples were collected by bronchoscope twice a weekly. BAL samples were analyzed by microscopic examination, fungal culture and galactomannan (GM) detection. The Platelia Aspergillus GM EIA was used to quantify GM indices. Samples with a BAL GM index > or = 1 were considered as positive for GM. Patients were classified as having probable or possible IA. Out of 36 suspected patients to IA, 36.1% of cases showed IA which were categorized as: 4 cases of possible IA and 9 of probable IA. 76.2% of BAL samples were positive for GM. From 13 patients with IA, 11 (84.6%) had at least one positive BAL GM index. Of these patients, 9 (81.8%) showed probable IA. The main underlying predisposing conditions were neutropenia (53.8%) and COPD (30.8%). Our study has indicated that COPD must be considered as one of the main predisposing condition for occurrence of aspergillosis in ICU patients. Our data have also revealed that GM detection in BAL samples play a significant role to IA diagnosis.