Limitações do teste de triagem de susceptibilidade a antifúngicos azóis em isolados ambientais de Aspergillus fumigatus

Abstract

Fungi of the genus Aspergillus are considered cosmopolitan and are associated with aspergillosis, infections that primarily affect immunocompromised individuals, representing a significant clinical and epidemiological challenge. The diagnosis of these infections involves host factors, clinical aspects, and laboratory findings, with treatment based on the use of triazole antifungals such as voriconazole, itraconazole, and posaconazole. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends screening tests as preliminary tools to identify possible fungal resistance, given that Antifungal Susceptibility Testing (AFST) requires often unavailable supplies. Therefore, this study evaluated the agreement between the screening test standardized by EUCAST and AFST results in 234 environmental isolates of Aspergillus fumigatus. The isolates were subjected to the screening test with itraconazole (4 mg/L), voriconazole (2 mg/L), and posaconazole (0.5 mg/L) and subsequently to AFST with the same antifungals at concentrations ranging from 0.03 to 16 mg/L. Data were analyzed using McNemar's test (significance level of 5%). The results demonstrated a significant difference in the proportions of resistance and susceptibility between the two methods for itraconazole (X² = 5.297; p = 0.021) and voriconazole (X² = 8.522; p = 0.003). For posaconazole, there was no statistically significant difference (X² = 0.063; p = 0.804). It is concluded, therefore, that the EUCAST screening protocol, validated for clinical samples, does not demonstrate the same efficacy for environmental isolates, highlighting the need to develop specific protocols for this type of sample.