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Journals / Mikrobiyoloji Bülteni / 2015 / Cilt: 49 - Sayı: 2

Evaluation of Common Commercial Systems for the Identifi cation of Yeast Isolates in Microbiology Laboratories: A Multicenter Study

Mikrobiyoloji Laboratuvarlarında Maya Türlerinin Tanımlanmasında Sık Kullanılan Ticari Sistemlerin Değerlendirilmesi: Çok Merkezli Bir Çalışma

Nilgün KARABIÇAK
Hatice ALTUN ULUDAĞ
Onur KARATUNA
GÜLŞEN HAZIROLAN
Neriman AKSU
Ali ADİLOĞLU
Işın AKYAR
Pages
210–220
DOI
—
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

The addition of morphological identifi cation to commercial systems will be useful for accurate diagnosis and treatment of mixed infections.

📌 3 Key Takeaways

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Objective & Hypothesis:Accurate and rapid identifi cation of yeast isolates have become important in recent years for not only antifungal susceptibility testing due to the species-specifi c clinical resistance breakpoints but also early initiation of appropriate antifungal therapy.
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Key Findings & Data:The aim of this study was to compare the two common commercial systems, VITEK 2 YST ID Card (Vitek; bioMérieux, France) and API 20C AUX (API; bioMérieux, France) with conventional mycological methods.
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Conclusion & Impact:The addition of morphological identifi cation to commercial systems will be useful for accurate diagnosis and treatment of mixed infections.
🔬Design:Research Article
📍Scope:Comprehensive Sample
⚙️Variables:Domain Parameters

Abstract

Accurate and rapid identifi cation of yeast isolates have become important in recent years for not only antifungal susceptibility testing due to the species-specifi c clinical resistance breakpoints but also early initiation of appropriate antifungal therapy. In clinical microbiology laboratories species identifi cation of yeasts is often performed with several commercial systems based on biochemical properties and rarely according to the physiological and morphological characteristics. The aim of this study was to compare the two common commercial systems, VITEK 2 YST ID Card (Vitek; bioMérieux, France) and API 20C AUX (API; bioMérieux, France) with conventional mycological methods. A total of 473 clinical yeast strains isolated from clinical specimens in different university and training/research hospitals and identifi ed by Vitek system were included in the study. The isolates were re-identifi ed with API and conventional methods including morphological identifi cation in the Mycology Reference Laboratory of the Public Health Institute of Turkey. Candida dubliniensis MYA 583, Candida krusei ATCC 6258, Candida parapsilosis ATCC 22019, Candida albicans ATCC 10231 and Cryptococcus neoformans ATCC 32268 were used as quality control strains and those standard strains were studied consecutively 10 days with both of the methods. The results of identifi cation by Vitek and API were compared with the results of conventional methods for those 473 yeast isolates [6 genus (Candida, Cryptococcus, Blastoshizomyces, Rhodotorula, Saccharomyces, Trichosporon), 17 species (5 common and 12 rarely isolated)]. The performances of the systems were better (Vitek: 95%; API: 96%) for the commonly detected species (C.albicans, C.parapsilosis, C.glabrata, C.tropicalis and C.krusei) than those for rarely detected species (Vitek: 78.4%; API: 71.6%) (p= 0.155). Misidentifi cation or unidentifi cation were mostly detected for C.parapsilosis (Vitek: 6/87; API: 7/87) and C.glabrata (Vitek: 9/104; API: 3/104) by both of the systems. For rarely detected yeast isolates, misidentifi cation or unidentifi cation were most frequently observed in species of C.pelliculosa (Vitek: 3/11; API: 6/11) and C.dubliniensis (API and Vitek: 2/5) isolates. Candida guilliermondii (API: 2/5) isolates had lower rate of identifi cation with API compared to other species. Blastoschizomyces capitatus and Saccharomyces cerevisiae isolates could not be identifi ed by both of the systems. As a result, the accurate diagnosis of Vitek and API systems were similar in terms of consistency (86.3%). Two systems performed well in correct identification of common clinical yeast species (at least 95%), while the identification of rare species was more challenging indicating that they require further morphological and physiological testing. The addition of morphological identifi cation to commercial systems will be useful for accurate diagnosis and treatment of mixed infections.

Özet

Son yıllarda türe özgü klinik direnç sınır değerlerinin belirlenmesi nedeniyle ve uygun antifungal tedaviye erken başlanması için maya türlerinin doğru ve hızlı tanımlanması önemlidir. Klinik laboratuvarlarda tanımlama, sıklıkla biyokimyasal özellikleri temel alan çeşitli ticari sistemlerle ve nadiren de fi zyolojik ve morfolojik özelliklere göre yapılmaktadır. Bu çalışmanın amacı, rutin laboratuvarlarda sık kullanılan Vitek 2 sistemi YST maya tanımlama kartı (Vitek; bioMérieux, Fransa) ve API 20C AUX (API; bioMérieux, Fransa) sisteminin konvansiyonel mikolojik tanı yöntemleriyle karşılaştırılmasıdır. Çalışmamızda, çeşitli üniversite ve eğitim/araştırma hastanelerinde klinik örneklerden izole edilen ve Vitek ile tanımlanan toplam 473 maya izolatı, Türkiye Halk Sağlığı Kurumu, Mikoloji Referans Laboratuvarı’nda, API sistemi ve morfolojik tanımlamayı da içeren konvansiyonel mikolojik yöntemler ile birlikte değerlendirilerek tür düzeyinde tanımlanmıştır. Çalışmada kalite kontrol suşları olarak Candida dubliniensis MYA 583, Candida krusei ATCC 6258, Candida parapsilosis ATCC 22019, Candida albicans ATCC 10231 ve Cryptococcus neoformans ATCC 32268 kullanılmış; standart suşlar her iki sistemle de ardarda 10 gün çalışılmıştır. Konvansiyonel yöntemler ile tanımlanan 473 klinik maya izolatının [6 cins (Candida, Cryptococcus, Blastoshizomyces, Rhodotorula, Saccharomyces, Trichosporon), 17 tür (5’i sık, 12’si nadir görülen)] Vitek ve API sonuçları karşılaştırıldığında; sistemlerin performansı, sık görülen türlerin (C.albicans, C.parapsilosis, C.glabrata, C.tropicalis ve C.krusei) tanımlanmasında (Vitek: %95; API: %96), nadir görülen türlerden (Vitek: %78.4; API: %71.6) daha iyi bulunmuştur (p= 0.155). Yanlış tanımlama veya tanımlayamama, her iki sistemle de, sık görülen türlerden en sık C.parapsilosis (Vitek: 6/87; API: 7/87) ve C.glabrata (Vitek: 9/104; API: 3/104) izolatlarında görülürken, nadir görülen türlerden C.pelliculosa (Vitek: 3/11; API: 6/11) ve C.dubliniensis (Vitek ve API: 2/5) izolatlarında saptanmıştır. API ile C.guilliermondii (API: 2/5) izolatlarının tanısı diğer türlere göre daha problemlidir. Blastoschizomyces capitatus ve Saccharomyces cerevisiae türleri, Vitek ve API ile tanımlanamamıştır. Sonuç olarak, Vitek ve API testlerinin doğru tanı koyma açısından tutarlılıkları benzer bulunmuş (%86.3); sık karşılaşılan türlerde tanımlama oranları daha yüksekken (en az %95) nadir görülen türlerde azaldığı dikkati çekmiştir. Ticari sistemlere morfolojik tanımlamanın da eklenmesi, tanıyı kolaylaştırmasının yanı sıra birden fazla etkenle meydana gelen enfeksiyonların doğru tanımlanması ve tedavisinde de yararlı olacaktır.

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Cite This Article

KARABIÇAK, N., ULUDAĞ, H. A., KARATUNA, O., HAZIROLAN, G., AKSU, N., ADİLOĞLU, A., AKYAR, I. (2015). Evaluation of Common Commercial Systems for the Identifi cation of Yeast Isolates in Microbiology Laboratories: A Multicenter Study. Mikrobiyoloji Bülteni, Cilt: 49 - Sayı: 2, 210–220. https://ajindex.com/articles/299585

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