Biofilm-forming ability profiling of Staphylococcus aureus and Staphylococcus epidermidis mastitis isolates
Biofilm-forming ability profiling of Staphylococcus aureus and Staphylococcus epidermidis mastitis isolates
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DOI：
10.1016/j.vetmic.2006.07.008
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发表时间：
2006-11-26
影响因子：
3.3
通讯作者：
Vilela, C. L.
中科院分区：
文献类型：
--
作者：
Oliveira, M.;Bexiga, R.;Vilela, C. L.
生物被膜形成能力已被越来越多地认为是葡萄球菌的重要毒力因子，促进其在宿主中的持久性，逃避其防御并允许细菌在高抗菌剂浓度下存活。金黄色葡萄球菌仍然是慢性乳腺炎的主要病原体，但近年来表皮葡萄球菌已成为相关的乳腺炎病原体。本研究旨在评价奶牛隐性乳房炎葡萄球菌田间分离株的生物被膜形成能力，并建立一种荧光原位杂交（FISH）技术，用于直接观察奶牛乳房炎葡萄球菌生物被膜的形成。金黄色葡萄球菌菌株产生生物被膜，而光密度测量只有18.75%的菌株显示这种表型。根据kappa系数检验（kappa = 0.259），结果显示出相当一致。关于S.表皮型乳腺炎菌株中，37.5%显示出产生生物膜的能力，但只有4个菌株通过所有方法均为阳性。该一致性为中度（kappa = 0.467）。人工污染的牛奶样品的FISH的应用程序允许直接观察生物膜生产的37.5%的菌株，显示与CRA结果的总协议。该方法更好地模拟了体内条件，特别是在钙和铁的存在方面，已知钙和铁分别以高浓度抑制或诱导生物膜产生。(c)2006 Elsevier B.V.保留所有权利。
Biofilm-forming ability has been increasingly recognized as an important virulence factor in Staphylococci, facilitating their persistence in the host, evading its defences and allowing bacterial survival at high antimicrobial concentrations. Staphylococcus aureus remains a major pathogen of chronic mastitis, but in the last years Staphylococcus epidermidis has emerged as a relevant mastitis pathogen. The present work aimed at the evaluation of the biofilm-forming ability of Staphylococci field isolates from bovine subclinical mastitis and at the development of a fluorescent in situ hybridisation (FISH) protocol that would allow the direct observation of biofilm formation in milk samples.The analysis of phenotypic expression in Congo Red Agar (CRA) and by FISH, showed that 37.5% of the S. aureus isolates produced biofilm, while by optical density measurement only 18.75% isolates revealed this phenotype. The results showed a fair agreement according to the kappa coefficient test (kappa = 0.259). Regarding S. epidermidis mastitis isolates, 37.5% revealed the ability to produce biofilm, but only four isolates were positive by all methods. This agreement was moderate (kappa = 0.467). The application of FISH to artificially contaminated milk samples allowed the direct observation of biofilm production by 37.5% isolates, showing total agreement with the CRA results. This method better mimics the in vivo conditions, especially in terms of the presence of calcium and iron, which in high concentrations, respectively, are known to inhibit or induce biofilm production. (c) 2006 Elsevier B.V. All rights reserved.