Mastitisli İneklerin Süt Örneklerinden Staphylococcus epidermidis İzolasyonu ve Biyofilm Oluşturma Yeteneğinin İncelenmesi

Abstract

Mastitis, süt sığırlarında görülen en önemli enfeksiyöz hastalıklardan biridir ve önemli ekonomik kayıplarla ilişkilidir. Etkenler arasında yer alan Staphylococcus epidermidis, biyofilm oluşturma yeteneği önemli bir virülens faktörü olarak kabul edilen fırsatçı bir patojendir. Bu çalışmanın amacı, sığır mastitisli süt örneklerinden elde edilen S. epidermidis izolatlarının biyofilm oluşturma kapasitesini fenotipik ve genotipik yöntemler kullanarak değerlendirmektir. Bu amaçla, İzmir ve Aydın illerindeki farklı işletmelerde bulunan klinik mastitisli 150 farklı süt sığırından toplam 150 süt örneği toplanmıştır. Örnekler %5 koyun kanlı agara ekilmiş ve izolatlar konvansiyonel yöntemler ile VITEK® 2 Compact sistemi kullanılarak tanımlanmıştır. Fenotipik biyofilm üretimi Kongo Red Agar (CRA) yöntemi ile değerlendirilmiş, icaA ve icaD genlerinin varlığı ise moleküler olarak incelenmiştir. Bakteriyolojik inceleme sonucunda 13 izolat S. epidermidis olarak tanımlanmıştır. Bunların 11’i (%84,6) CRA yöntemi ile biyofilm pozitif, 2’si (%15,4) ise biyofilm negatif olarak değerlendirilmiştir. Moleküler analiz sonucunda ise izolatların hiçbirinde icaA veya icaD geni saptanmamıştır. Sonuç olarak, mastitisli süt örneklerinden elde edilen S. epidermidis izolatlarının büyük çoğunluğu, araştırılan klasik biyofilm ile ilişkili genlerin yokluğuna rağmen fenotipik olarak biyofilm oluşturma yeteneği göstermiştir. Bu bulgular, sığırlara ait S. epidermidis izolatlarında biyofilm oluşumunun alternatif moleküler mekanizmalar içerebileceğini ve fenotipik sonuçların genotipik analizlerle birlikte değerlendirilmesi gerektiğini düşündürmektedir.

Keywords

• Biyofilm oluşumu
• Mastitis
• Sığır
• Staphylococcus epidermidis
• Süt

Isolation of Staphylococcus epidermidis from Milk Samples of Cows with Mastitis and Investigation of Its Biofilm Formation Ability

Abstract

Mastitis is one of the most important infectious diseases in dairy cattle and is associated with considerable economic losses. Among the causative agents, Staphylococcus epidermidis is an opportunistic pathogen whose ability to form biofilm is considered an important virulence factor. The aim of this study was to evaluate the biofilm-forming capacity of S. epidermidis isolates recovered from bovine mastitic milk samples using phenotypic and genotypic methods. For this purpose, a total of 150 milk samples were collected from 150 different dairy cows with clinical mastitis from different farms in the provinces of İzmir and Aydın. The samples were cultured on 5% sheep blood agar, and the isolates were identified by conventional procedures and the VITEK® 2 Compact system. Phenotypic biofilm production was evaluated by the Congo Red Agar (CRA) method, and the presence of the icaA and icaD genes was investigated molecularly. As a result of bacteriological examination, 13 isolates were identified as S. epidermidis. Of these, 11 (84.6%) were found to be biofilm-positive by the CRA method, whereas 2 (15.4%) were biofilm-negative. Molecular analysis revealed that none of the isolates carried the icaA or icaD genes. In conclusion, most S. epidermidis isolates obtained from mastitic milk samples showed phenotypic biofilm-forming ability despite the absence of the investigated classical biofilm-associated genes. These findings suggest that biofilm formation in bovine S. epidermidis isolates may involve alternative molecular mechanisms and that phenotypic results should be interpreted together with genotypic analyses.

Keywords

• Biofilm formation
• Cattle
• Mastitis
• Milk
• Staphylococcus epidermidis

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