Candida İzolatlarının Antifungal Duyarlılığının Belirlenmesinde Klinik Laboratuvar Standartları Enstitüsü (CLSI) ve Avrupa Antimikrobiyal Duyarlılık Testleri Komitesi (EUCAST) Sıvı Mikrodilüsyon Yöntemlerinin Karşılaştırılması

Abstract

Candida species are among the top 10 pathogens causing bloodstream infections associated with high morbidity, mortality. In spite of the development of new antifungal drugs, epidemiological studies have shown that resistance to antifungal drugs among Candida isolates is becoming a serious problem. The aim of this study was to compare the antifungal broth microdilution methods of the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole and anidulafungin susceptibility of Candida blood isolates. The study consisted of 74 Candida albicans, 67 Candida parapsilosis, 30 Candida glabrata, and 18 Candida tropicalis isolates. The minimum inhibitory concentrations were determined after 24 and 48 hour of incubation with CLSI method and only 24 hour of incubation with EUCAST method except anidulofungin. The MIC values obtained by both methods were considered to be compatible within ± 2 dilution limits. The categorical agreement between methods for each antifungal agent was assessed using clinical break points and epidemiological cut-off values. The agreement (± 2 dilution) between the methods was found to be species, drug, and incubation time dependent. After 24 hour incubation, good agreement category (> 90%) was detected between amphotericin B, itraconazole, posaconazole and anidulofungin, but was lower category (< 85%) was determined with fluconazole and voriconazole especially for relatively slow growing C.glabrata and C.parapsilosis isolates. Excellent categorical agreement (100%) was observed for amfoterisin B/C.parapsilosis, C.glabrata, C.tropicalis and anidulofungin/C.albicans, C.glabrata, C.tropicalis but least category was determined for posaconazole and C.albicans (71.6% at 24 hour; 73% at 48 hour). In vitro resistance of therapeutically used fluconazole and anidulafungin determined by both methods was rare among C.albicans (1.3%, 2.7% respectively), C.glabrata (0%, 3.3% respectively) and C.tropicalis (0%, 5.6% respectively) isolates but, an increase of non-susceptible isolates were observed among C.parapsilosis (11.9% at 24 hour of incubation; 17.9% at 48 hour of incubation) for fluconazole. There was also a cross resistance between fluconazole and voriconazole for three C.parapsilosis isolates and one multidrug resistant (fluconazole, itraconazole, posaconazole and anidulofungin) C.albicans isolate (fluconazole, itraconazole, posaconazole and anidulofungin). As a result in this study, it was determined thatboth methods were similar and can be used according to preference of laboratories. The CLSI antifungal susceptibility test results can be assessed at the end of 24 hour incubation, but sometimes it is important that the evaluation should be performed as a result of 48 hour incubation in slow growing species such as C.glabrata.

Clinical Efficacy of Polymyxin B in Patients Infected with Carbapenem-Resistant Organisms

“…According to the European Committee on Antimicrobial Susceptibility Testing (EUCAST, v8.0, 2018), bacteria were resistant to colistin if their MICs were >2 mg/L. 16 …”

Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

“…This strain has been previously characterized for its response to different commercial antifungals and it was shown to be resistant to three different azoles (Fluconazole, Voriconazole, Ketoconazole) [35]. This clinical isolate has been subsequently evaluated in vitro following the methodology recommended by the Clinical and Laboratory Standards Institute (CLSI) [36], and it was shown to be clotrimazole sensitive (data not shown in this manuscript).…”

“…The minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) were measured according to the methodologies recommended by the Clinical Laboratory and Standards Institute [36]. The experiment has been performed in sterile Nunc TM Microwell TM 96-well microplates (Thermo Fisher Scientific).…”

Broadened glycosylation patterning of heterologously produced erythromycin

“…The filter disks were then loaded with 5 µl of a given erythromycin deoxysugar analog, and the plates were incubated at 30°C overnight. Liquid-based MIC assays were conducted according to the protocol outlined by the Clinical and Laboratory Standards Institute (Dalyan Cilo et al, 2018) for 24 hr.…”