Azole resistance in strains of Aspergillus fumigatus sensu stricto isolated from respiratory clinical samples

Guevara J.; Villanueva-Cotrina F.; Quispe B.C.; Sánchez C.C.; Sanchez-Perez J.; Ulffe G.V.; García-Effrón G.; Gamarra S.; Castillo V.B. · Anales de la Facultad de Medicina (2023) · DOI: 10.15381/anales.v84i4.26323

Resumen

Introduction.InvasiveAspergillosis(IA)posesasignificantthreattopatientswithchronicdiseasesandcompromisedimmune systems,withAspergillusfumigatussensustricto(AFSS)beingtheprimaryetiological agent.Accurateandtimelydiagnosis is crucial, particularly given the rising incidence of IA strains resistant to antifungals, necessitating molecular methods for typing. Methods. Twenty strains from Instituto de Medicina Tropical - Universidad Nacional Mayor de San Marcos, mycological collection, previously identified as Aspergillus fumigatus sensu lato through macroscopic and microscopic analysis, were studied. These strains were forwarded to the Universidad Nacional del Litoral for AFSS typing using a PCR screening based on CYP51A gene sequences. Antifungal susceptibility testing was performed for Voriconazole (VOR), Itraconazole (ITC), Posaconazole (POS), Isavuconazole (ISA), Anidulafungin (ANF), Caspofungin (CSF), and Amphotericin B (AMB), obtaining Minimum Inhibitory Concentrations (MICs) according to CLSI M38M51S-Ed3. Results. All 20 strains were identified as AFSS. None of the strains exhibited MICs above the clinical breakpoint (VOR) or the epidemiological cutoffs (ITC, ISA, AMB, and CSF). POS demonstrated the highest potency against the strain collection, with a geometric mean MIC of 0,042 µg/ml. Conclusions. All isolates were classified as azole-sensitive Aspergillus fumigatus sensu stricto (AFSS) based on clinical cutoff points, particularly posaconazole, which exhibited superior antifungal activity. Our findings contribute to augmentingthe limitedinformation on the etiology andclinical antifungal sensitivity of IAin our country.

Instituciones: Universidad Nacional Mayor de San Marcos