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: TR34-L98H (n = 41), G54R (n = 5), TR46-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 TR34-L98H, G54R, or TR46-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.
OBJECTIVE: 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.
摘要:
可以通过使用含唑的琼脂平板(E.Def10.2程序);然而,分生孢子悬浮液过滤和接种物制备前的接种物调整是耗时的。我们评估了跳过过滤和接种物调整步骤是否会对E.Def10.2程序的性能产生负面影响。烟曲霉严格分离株(n=98),以前分类为唑类敏感或唑类耐药(E.Def9.4方法),被研究过。抗唑分离株具有野生型cyp51A基因序列(n=1)或以下cyp51A基因取代:TR34-L98H(n=41),G54R(n=5),TR46-Y121F-T289A(n=1),或G448S(n=1)。根据EUCASTE.Def10.2程序制备内部含唑的琼脂平板。将通过添加蒸馏水(吐温20±0.1%)获得的分生孢子悬浮液过滤并将接种物调节至0.5McFarland或保持未过滤和未调节。使用每种程序制备的接种物的琼脂筛选方法之间的协议对于伊曲康唑(99%)很高,伏立康唑(100%),泊沙康唑(94.9%)。E.Def10.2的敏感性和特异性(考虑按照微量稀释E.Def9.4方法的敏感性类别作为金标准)为100%,以排除或排除使用未经过滤和未经调整的悬浮液时的抗性;携带TR34-L98H的分离株的抗性表型,G54R,或正确检测到TR46-Y121F-T289A取代。未过滤和未调节的分生孢子悬浮液不会对E.Def10.2方法的性能产生负面影响,当筛选烟曲霉的唑抗性时。
目的:可以通过使用含唑的平板常规进行烟曲霉中的唑抗性筛选(E.Def10.2程序);然而,在接种平板之前,分生孢子悬浮液过滤和接种物调整是耗时的。我们,在这里,结果表明,当筛选烟曲霉对唑的抗性时,未过滤和未调节的分生孢子悬浮液不会对E.Def10.2方法的性能产生负面影响。