Nikolina RUSENOVA, Wondwossen GEBREYES, Mariana KOLEVA, Jurii MITEV, Toncho PENEV, Nasko VASILEV, Tchonka MITEVA

Comparison of three methods for routine detection of Staphylococcus aureus isolated from bovine mastitis

Bu çalışma Bovin mastitis etkeni olarak Staphylococcus aureusun belirlenmesinde rutin olarak kullanılan üç tespit yöntemini karşılaştırmayı amaçlamaktadır. Denenen yöntemler şunlardır; konvensiyonel biyokimyasal metot, ticari tespit sistem BioLog (Gen III MicroPlate) ve polimeraz zincir reaksiyonu (PZR) ile amplifiye edilmiş tür spesifik gen (nuc). Bulgaristandaki farklı çiftliklerde subklinik ve klinik mastitisli sütçü ineklerden alınan 453 adet örnekten toplam 73 staphilococal izolat elde edildi. Konvensiyonel metotlarla bu izolatların 60ı koagulaz pozitif, 3ü katalaz negatif ve 10u koagulaz negatif olarak belirlendi. BioLog sistemi ile 72 izolat S. аureus subsp. aureus olarak tespit edilirken bir adet koagulaz pozitif izolat S. schleiferi subsp. coagulans olarak belirlendi. PZR ile nuc geninin amplifikasyonu kullanılarak BioLog sistemi ile S. аureus subsp. aureus olarak tespit edilen izolatlar teyit edildi. Koagulaz seviyesine dayanarak S. aureusun primer identifikasyonu 14 (%19,2) hatalı tespite neden oldu. Bu bulgulara dayanarak BioLog sistem ve PZR, S. aureusun sütten tespitinde daha güvenilir yöntemler olarak belirlendi. Sonuç olarak, bu çalışma ile rutin olarak fenotipik ve moleküler tespit yöntemlerinin beraber kullanılmasının sütten S. aureusun tespitinde başarıyı artıracağı ortaya konuldu.

Bovin mastitislerde Staphylococcus aureusun rutin tespitinde üç metodun karşılaştırılması

The present study aimed to compare three identification methods that are routinely used for the detection of Staphylococcus aureus as bovine mastitis agent. The evaluated methods were as followed: conventional biochemical method, commercial identification system BioLog (Gen III MicroPlate) and amplification of species-specific gene (nuc) by polymerase chain reaction (PCR). A total of 73 staphylococcal isolates were collected from 453 individual milk samples from dairy cows with subclinical and clinical mastitis from different farms in Bulgaria. This isolates were determined as 60 coagulase-positive, 3 catalase-negative and 10 coagulase-negative by conventional methods. BioLog system identified 72 isolates as S. аureus subsp. aureus and one coagulase-positive isolate as S. schleiferi subsp. coagulans. PCR amplification of nuc gene further confirmed S. аureus subsp. aureus isolates identified by the BioLog system. The primary identification of S. aureus on the basis of coagulase level led to erroneous determination of 14 (19.2%) of the isolates. Based on the findings, BioLog system and PCR appear to be more reliable detection systems for S. aureus from milk. In conclusion, the present study showed that a routine approach using a combination of phenotypic and molecular detection systems could improve S. aureus detection in milk.

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