Azole resistance screening in Aspergillus fumigatus sensu stricto using the azole-containing agar method (EUCAST E.Def 10.2): conidial suspension filtration and inoculum adjustment before inoculum preparation may not be needed

Media type: E-Article

Title: Azole resistance screening in Aspergillus fumigatus sensu stricto using the azole-containing agar method (EUCAST E.Def 10.2): conidial suspension filtration and inoculum adjustment before inoculum preparation may not be needed

Contributor: Serrano-Lobo, Julia; Reigadas, Elena; Muñoz, Patricia; Escribano, Pilar; Guinea, Jesús; Romera, Waldo Sánchez-Yebra; Sánchez-Gómez, Juan Antonio; Lozano, Inmaculada Guerrero; Tejero-García, Rocío; Martínez, Fernando Cobo; Viñuela, Laura; de Luna, Francisco Franco-Álvarez; Oya, Ana Lara; Moreno-Torres, Isabel Casanovas; Ruiz, María Pilar Bermúdez; Barrenechea, Ana Isabel Suárez; Méndez, Carmen Castro; de Pipaón, Maite Ruiz Pérez; Condado, Héctor Condado; Sánchez, Rocío Cebollada; Gómez, Concepción López; Romero, Emilio David Valverde; Pérez, Henar Villar; Temprano, Marta Arias; [...]

Published: American Society for Microbiology, 2024

Language: English

DOI: 10.1128/jcm.00369-24

ISSN: 0095-1137; 1098-660X

Origination:

Footnote:

Description: ABSTRACT Azole resistance screening in Aspergillus fumigatus sensu stricto can be routinely carried out by using azole-containing agar plates (E.Def 10.2 procedure); however, conidial suspension filtering and inoculum adjustment before inoculum preparation are time-consuming. We evaluated whether skipping the filtration and inoculum adjustment steps negatively influenced the performance of the E.Def 10.2 procedure. A. fumigatus sensu stricto isolates ( n = 98), previously classified as azole susceptible or azole resistant (E.Def 9.4 method), were studied. Azole-resistant isolates had either the wild-type cyp51A gene sequence ( n = 1) or the following cyp51A gene substitutions: TR 34 -L98H ( n = 41), G54R ( n = 5), TR 46 -Y121F-T289A ( n = 1), or G448S ( n = 1). In-house azole-containing agar plates were prepared according to the EUCAST E.Def 10.2 procedure. Conidial suspensions obtained by adding distilled water (Tween 20 0.1%) were either filtered and the inocula adjusted to 0.5 McFarland or left unfiltered and unadjusted. Agreements between the agar screening methods using inocula prepared by each procedure were high for itraconazole (99%), voriconazole (100%), and posaconazole (94.9%). Sensitivity and specificity (considering the susceptibility category as per the microdilution E.Def 9.4 method as the gold standard) of E.Def 10.2 were 100% to rule in or rule out resistance when unfiltered and unadjusted suspensions were used; the resistance phenotype of isolates harboring the TR 34 -L98H, G54R, or TR 46 -Y121F-T289A substitutions was correctly detected. Unfiltered and unadjusted conidial suspensions do not negatively influence the performance of the E.Def 10.2 method when screening for azole resistance in A. fumigatus sensu stricto . IMPORTANCE Azole resistance screening in Aspergillus fumigatus sensu stricto can be routinely carried out by using azole-containing plates (E.Def 10.2 procedure); however, conidial suspension filtering and inoculum adjustment before inoculation of plates are time-consuming. We, here, showed that unfiltered and unadjusted conidial suspensions do not negatively influence the performance of the E.Def 10.2 method when screening for azole resistance in A. fumigatus sensu stricto .

Search in field:

Recently searched for: