Filamentous fungi, and their antifungal susceptibilities, isolated from patients at an oncology hospital in Turkey

Abstract

Background

Fungal infections affect especially to patients with cancer and those who are immunocompromised.

Aims

We analyzed the prevalence of filamentous fungi in patients at Ankara Oncology Education and Research Hospital from 2022 to 2024; antifungal susceptibility tests were also carried out.

Methods

Filamentous fungi were analyzed by MALDI-TOF (matrix-assisted laser desorption ionization-time of flight), and antifungal susceptibility was tested by the broth microdilution method.

Results

Filamentous fungi were recovered from 66 (6.5%) of 1020 samples: 31(47%) deep tracheal aspirates, 13 (19.7%) sputum, 10 (15.2%) ear swabs, 9 (13.6%) biopsies, and three (4.5%) bronchoalveolar lavage samples. Filamentous fungi other than Aspergillus grew from 10 (15.2%) samples, while Aspergillus species were recovered in 56 (84.8%). Of the 56 Aspergillus, 21 (31.8%) were Aspergillus fumigatus, 15 (22.7%) were Aspergillus flavus, 14 (21.2%) were Aspergillus niger, 3 (4.5%) were Aspergillus terreus, and one strain (1.5%) each of the following species were identified: Aspergillus tamarii, Aspergillus nidulans, and Aspergillus calidoustus. Of 66 patients from whom a fungal isolate was recovered, 50 (75.8%) had cancer.

Minimum inhibitory concentrations (MICs) were determined in 45 (80.4%) Aspergillus isolates. Eight (8/19) A. fumigatus, seven (7/13) A. flavus, and three (3/11) A. niger were non-wild type (WT) according to amphotericin B MIC values. Four (4/13) A. flavus and two (2/19) A. fumigatus were non-WT according to itraconazole MIC values. One (1/13) A. flavus was non-WT according to voriconazole MIC value.

Conclusions

The filamentous fungi recovered from the patients showed high antifungal MIC/MEC values, and some isolates had high amphotericin B MICs. Voriconazole was effective in vitro against A. fumigatus.

Resumen

Antecedentes

Las infecciones fúngicas afectan de manera importante a pacientes inmunocomprometidos y pacientes con cáncer.

Objetivos

Analizamos la prevalencia de hongos filamentosos y sus valores de sensibilidad antifúngica obtenidos con ensayos in vitro.

Métodos

Nuestro análisis incluyó retrospectivamente a pacientes del Hospital de Educación e Investigación Oncológica de Ankara entre 2022 y 2024. Los hongos filamentosos fueron identificados mediante MALDI-TOF (matrix-assisted laser desorption ionization-time of flight).

Resultados

Se obtuvo crecimiento de hongos filamentosos en 66 (6,5%) de 1020 muestras: 31 (47%) de aspirado traqueal profundo, 13 (19,7%) de esputo, 10 (15,2%) de oído, 9 (13,6%) de biopsias y 3 (4,5%) de lavado broncoalveolar. Se identificaron especies no pertenecientes al género Aspergillus en 10 (15,2%) muestras, mientras que Aspergillus se recuperó de 56 (84,8%) muestras, con la siguiente distribución de especies: 21 (31,8%) Aspergillus fumigatus, 15 (22,7%) Aspergillus flavus, 14 (22,1%) Aspergillus niger, 3 (4,5%) Aspergillus terreus, y un aislamiento (1,5%) en cada caso de las especies Aspergillus tamarii, Aspergillus nidulans y Aspergillus calidoustus. De los 66 pacientes, 50 (75,8%) tenían un diagnóstico de cáncer.

Se obtuvieron valores de concentración mínima inhibitoria (CMI) de 45 aislamientos de Aspergillus (80,4%). Ocho (8/19) aislamientos de A.fumigatus, siete (7/13) de A.flavus y tres (3/11) de A.niger mostraron un fenotipo no-WT (wild type) según su sensibilidad a la anfotericina B. Cuatro (4/13) aislamientos de A.flavus y dos (2/19) aislamientos de A.fumigatus fueron igualmente catalogados no-WT según su sensibilidad al itraconazol. En relación con la sensibilidad al voriconazol, un (1/13) aislamiento de A. flavus fue considerado no-WT.

Conclusiones

Los hongos filamentosos aislados mostraron valores CMI altos, incluso para la anfotericina B. El voriconazol fue efectivo in vitro contra A.fumigatus.