Resumen

MORENO CALDERON, Xiomara; MACERO ESTEVEZ, Carolina  y  OLIVEIRA OLIVEIRA, Débora. Antifungal susceptibility of Aspergillus genus determined by the Etest® method: eleven years of experience at the Instituto Médico La Floresta. Caracas, Venezuela. Invest. clín [online]. 2023, vol.64, n.4, pp.471-481.  Epub 22-Dic-2023. ISSN 0535-5133.  https://doi.org/10.54817/ic.v64n4a04.

This research aimed to determine the susceptibility of Aspergillus spp. to four antifungal agents using the Etest® method in several clinical samples (respiratory samples, soft tissue, otic tissue, and ocular tissue, among others) from a private health center in Venezuela. Thirty-three strains were evaluated: 11 Aspergillus section Flavi, eight Aspergillus section Fumigati, six Aspergillus section Nigri, four Aspergillus section Terrei, and four Aspergillus spp. A 0.5 McFarland standard suspension of a 5-day culture of each Aspergillus strain was prepared on Potato Dextrose agar and then inoculated on Sabouraud agar plates with 2% glucose. Voriconazole (VCZ), amphotericin B (AMB), caspofungin (CAS), and posaconazole (PCZ) were tested. Minimal inhibitory concentrations (MIC) in μg/mL were determined after 24 and 48 hours of incubation at 35 °C and th range (R), geometric mean (GM), MIC50, and MIC90 were calculated. The results for the 33 Aspergillus spp. tested after 24 h were the following: VCZ (R = 0.031- 16; GM = 0.145; MIC50 = 0.125 and MIC90 = 0.5), AMB (R = 0.031-16; GM = 0.644; MIC50 = 0.5 and MIC90 = 8), CAS (R = 0.031-16; GM = 0.1076; MIC50 = 0.063 and MIC90 = 1), PCZ (R =0.031 - 0.5; GM = 0.0755; MIC50 = 0.063 and MIC90 = 0.25). This investigation allowed assessing the antifungal susceptibility profiles of Aspergillus spp. isolated from clinical samples by the Etest® method, which is practical, reproducible and easy to perform in microbiology laboratories.

Palabras clave : susceptibility; Aspergillus spp; cryptic species; antifungals; Etest diffusion method; minimal inhibitory concentration.

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