Effective detection of azole resistance in Aspergillus fumigatus sensu stricto using a gradient diffusion plastic strip: A comparison of filtered-adjusted vs. unfiltered-unadjusted inocula.

IF 2.7 3区医学 Q3 INFECTIOUS DISEASES

Medical mycology Pub Date : 2025-01-25 DOI:10.1093/mmy/myaf011

Julia Serrano-Lobo, Elena Reigadas, Patricia Muñoz, Pilar Escribano, Jesús Guinea

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引用次数: 0

Abstract

Gradient diffusion plastic strips are utilized for azole susceptibility testing against Aspergillus fumigatus in some clinical microbiology laboratories; however, they lack proper validation. We evaluated the performance of this method for detecting azole resistance in A. fumigatus sensu stricto, and we assessed whether skipping filtration and inoculum adjustment of conidial suspensions negatively influenced its performance. A total of 98 A. fumigatus sensu stricto isolates, previously classified as azole-susceptible or resistant, were studied. Azole-resistant isolates had specific cyp51A gene mutations, including TR34-L98H ± S297T-F495I, G54R, TR46-Y121F-T289A, and G448S. Conidial suspensions were prepared following the principles of the E.Def 9.4 method or left unfiltered and unadjusted. Based on minimum inhibitory concentration (MIC) distributions obtained with the gradient diffusion plastic strip using both types of inoculum preparations, cutoff values were proposed to classify isolates as resistant: >1 mg/l for itraconazole and voriconazole and >0.25 mg/l for posaconazole. These cutoffs coincided with EUCAST breakpoints and correctly classified all except one (TR46-Y121F-T289A) isolate. High essential agreement values (95.9%-98%) were obtained, regardless of inoculum preparation. Overall, sensitivity/specificity values of the gradient diffusion plastic strip using the proposed cutoff values for itraconazole (100%/98%), voriconazole (100%/100%), and posaconazole (100%/98%) to screen for azole resistance were not impacted by the inoculum preparation method. Thus, the gradient diffusion plastic strip is a reliable method for screening azole resistance in A. fumigatus isolates using the proposed MIC cutoffs, and inoculum preparation without filtration and adjustment of conidial suspensions did not negatively influence the performance of the method.

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梯度扩散塑料条法检测严格感烟曲霉对唑的抗性：过滤调整与未过滤调整接种物的比较

一些临床微生物实验室采用梯度扩散塑料条进行烟曲霉药敏试验，但缺乏适当的验证。本研究评价了该方法检测严格感烟曲霉（A. fumigatus stricu）耐药性的性能，并评估了跳过过滤和接种量调整是否会对该方法的性能产生负面影响。共对98株严格感烟螨进行了研究，这些菌株以前被分类为唑敏感或耐药。耐唑菌株存在特异性cyp51A基因突变，包括TR34-L98H±S297T-F495I、G54R、TR46-Y121F-T289A和G448S。分生孢子混悬液按照E.Def 9.4法制备，或不过滤、不调整。根据梯度扩散塑料条获得的两种接种制剂的最小抑制浓度（MIC）分布，提出了将菌株分类为耐药的临界值：伊曲康唑和伏立康唑为>0 1 mg/L，泊沙康唑为> 0.25 mg/L。这些截止点与EUCAST断点一致，并正确分类了除一个（TR46-Y121F-T289A）分离物外的所有分离物。无论接种方式如何，均获得较高的基本一致性值（95.9%-98%）。总体而言，采用建议的伊曲康唑（100%/98%）、伏立康唑（100%/100%）和泊沙康唑（100%/98%）临界值筛选抗唑药物的梯度扩散塑料条的敏感性/特异性不受接种制备方法的影响。因此，梯度扩散塑料条法是一种可靠的烟曲霉耐药筛选方法，该方法采用MIC切断法，接种剂制备无需过滤，分生菌悬浮液的调整对方法的性能没有负面影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Medical mycology 医学-兽医学

CiteScore

5.70

自引率

3.40%

发文量

632

审稿时长

12 months

期刊介绍： Medical Mycology is a peer-reviewed international journal that focuses on original and innovative basic and applied studies, as well as learned reviews on all aspects of medical, veterinary and environmental mycology as related to disease. The objective is to present the highest quality scientific reports from throughout the world on divergent topics. These topics include the phylogeny of fungal pathogens, epidemiology and public health mycology themes, new approaches in the diagnosis and treatment of mycoses including clinical trials and guidelines, pharmacology and antifungal susceptibilities, changes in taxonomy, description of new or unusual fungi associated with human or animal disease, immunology of fungal infections, vaccinology for prevention of fungal infections, pathogenesis and virulence, and the molecular biology of pathogenic fungi in vitro and in vivo, including genomics, transcriptomics, metabolomics, and proteomics. Case reports are no longer accepted. In addition, studies of natural products showing inhibitory activity against pathogenic fungi are not accepted without chemical characterization and identification of the compounds responsible for the inhibitory activity.