Investigation of Antifungal Susceptibility of Candida Species Isolated from Various Clinical Samples with Disc Diffusion Method

Abstract

Aim: Increasing frequency of infections due to Candida species in recent years and widespread use of empirical antifungal cause the development of resistant Candida strains and increased resistance rates. Therefore, the need for in vitro antifungal susceptibility tests is increasing in selecting appropriate and effective antifungal treatments. Material and Methods: In this study, Candida strains isolated from various clinical specimens from Düzce University Clinical Microbiology Laboratory were typed and their susceptibility to antifungal agents were investigated. Identification of origins were made using conventional and auotomatic methods. Antifungal susceptibilities of strains were determined by disc diffusion method. The interpretation of zone diameters was performed according to the CLSI M44-S3 document for voriconazole and fluconazole, and according to the recommendations of Rosco Diagnostica, the manufacturer of Neo-Sensitabs tablets, for posaconazole, caspofungin, and itraconazole. No threshold values have been established for amphotericinB and flucytosine. Results: According to this study 156 Candida strains were found as 89 (57.1%) C. albicans, 48 (30.8%) C. glabrata, 11 (7.1%) C. tropicalis, 2(1.5%) C. lusitaniae, 2 (1.3%) C. kefyr, 2 (1.3%) C. parapsilosis and 2 (1.3%) C. guilliermondii. When the antifungal susceptibilities of strains were examined, antifungals with the highest resistance were detected as itraconazole (64.1%); the antifungals with the highest susceptibilities were as caspofungin (98.7%), voriconazole (94.2%), fluconazole (85.3%) and the highest dose dependent susceptibilities were determined as itraconazole (34.6%) and posacanozole (11.5%) respectively. The mean zone diameters for amphotericin B and flucytosine were measured as 15.29 (± 3), 17.06 (± 9.8) respectively. Conclusion: Identification of agents for proper treatment of Candida species and testing of antifungal susceptibility tests of isolated strains will contribute to empirical antifungal treatment policies.

Keywords

• antifungal susceptibility
• candida
• disc diffusion

Çeşitli Klinik Örneklerden İzole Edilen Candida Türlerinin Antifungal Duyarlılıklarının Disk Difüzyon Yöntemiyle Araştırılması

Abstract

Amaç: Son yıllarda Candida türlerine bağlı infeksiyonların sıklığının giderek artması ve ampirik antifungal kullanımının yaygınlaşması, dirençli Candida suşlarının ortaya çıkmasına ve direnç oranlarının artmasına neden olmaktadır. Bu nedenle uygun ve etkin antifungal tedavinin seçiminde in vitro antifungal duyarlılık testlerine gereksinim artmaktadır. Gereç ve Yöntemler: Bu çalışmada, Düzce Üniversitesi Tıbbi Mikrobiyoloji Laboratuvarı’na gelen çeşitli klinik örneklerden izole edilen Candida suşları tiplendirilerek antifungal ajanlara karşı duyarlılıkları araştırıldı. Kökenlerin tanımlanması konvansiyonel ve otomatize yöntemler kullanılarak yapıldı. Suşların antifungal duyarlılıkları Kirby-bauer disk difüzyon yöntemi ile yapıldı. Zon çaplarının yorumlanması, vorikonazol ve flukonazol için CLSI M44-S3 dokümanına göre, posakonazol, kaspofungin ve itrakonazol için ise NeoSensitabs tabletlerinin üretici firması olan Rosco Diagnostica’nın önerilerine göre yapılmıştır. Amfoterisin B ve flusitozin için ise kabul edilmiş sınır değerler literatürde saptanamamıştır. Bulgular: Çalışmaya dahil edilen 156 Candida suşunun 89’u (%57,1) C. albicans, 48’i (%30,8) C. glabrata, 11’i (%7,1) C. tropicalis, 2’si (%1,5) C. lusitaniae, 2’si (%1,3) C. kefyr, 2’si (%1,3) C. parapsilosis ve 2’si (%1,3) C. guilliermondii olarak saptanmıştır. Suşların antifungal duyarlılıkları incelendiğinde en fazla direnç saptanan antifungal itrakonazol (%64,1); en fazla duyarlılık saptanan antifungaller sırasıyla kaspofungin (%98,7), vorikonazol (%94,2), flukonazol (%85,3) en fazla doza bağlı duyarlılık saptanan antifungaller ise sırasıyla itrakonazol (%34,6) ve posakanozol (%11,5) olarak saptanmıştır. Amfoterisin B ve flusitozin için belirlenen ortalama zon çapları sırasıyla 15,29 (±3) ve 17,06 (±9,8) olarak ölçülmüştür. Sonuç: Sonuç olarak, Candida türlerinin uygun tedavisi için etkenlerin tür tanımlaması ve izole edilen kökenlerin antifungal duyarlılık testlerinin yapılması ampirik antifungal tedavi politikalarına katkı sağlayacaktır.

Keywords

• antifungal duyarlılık
• candida
• disk difüzyon

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