Vasil' M, Farkasova Z, Elecko J, Illek J, Zigo F
Institute of Animal Breeding, Department of Nutrition, Dietetics and Animal Breeding, University of Veterinary Medicine and Pharmacy, Komenskeho 73, 041 84 Kosice, the Slovak Republic.
Clinical Laboratory for Large Animals, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, the Czech Republic.
Pol J Vet Sci. 2017 Dec;20(4):795-801. doi: 10.1515/pjvs-2017-0100.
In this study we investigated 24 strains of Staphylococcus aureus and 33 strains of Staphylococcus epidermidis isolated from milk of sheep with clinical mastitis, for their ability to form biofilms. Three methods for the determination of a biofilm were used. When evaluating the growth on Congo Red agar (CRA), 79.2% S. aureus strains and 72.7% S. epidermidis strains were positive for biofilm formation. The quantitative method of biofilm detection on a Microtitre Plate (MTP) revealed positive results for 75.0% of S. aureus samples and 75.8% for S. epidermidis samples. Using PCR method for determination of the presence of genes that affect formation of biofilms, the most frequently determined genes were eno in both S. aureus (18/24; 75.0%) and S. epidermidis strains (20/33; 60.6%). The genes icaAB and ebpS were detected in both S. aureus and S. epidermidis strains, and similarity between these strains was 12.5% - 15.1% and 4.2% - 6.0%, respectively. The bap was recorded only in S. epidermidis (3.0%). Statistical comparison of the level of biofilm formation was performed using Chi square test. There were no statistically significant differences in the amount of biofilm formation between two methods for detection of biofilm CRA and MTP (p>0.05). Comparison of all six monitored parameters showed no dependence of characteristics of the tested strains S. aureus and S. epidermidis at significance level α = 0.05. Biofilm formation by the bacteria isolated from 57 cases of clinical mastitis in sheep was confirmed. Sensitivity and specificity of the CRA method for S. aureus were 94.44% and 66.66%, respectively, and for S. epidermidis 92.0% and 87.5%, respectively. Both CRA and MTP methods can be recommended for the detection of biofilm production by S. aureus and S. epidermidis strains isolated from milk of sheep with clinical mastitis.
在本研究中，我们调查了从患有临床乳腺炎的绵羊乳汁中分离出的24株金黄色葡萄球菌和33株表皮葡萄球菌形成生物膜的能力。使用了三种生物膜测定方法。在刚果红琼脂（CRA）上评估生长情况时，79.2%的金黄色葡萄球菌菌株和72.7%的表皮葡萄球菌菌株生物膜形成呈阳性。微量滴定板（MTP）上生物膜检测的定量方法显示，75.0%的金黄色葡萄球菌样本和75.8%的表皮葡萄球菌样本结果呈阳性。使用PCR方法测定影响生物膜形成的基因的存在情况，在金黄色葡萄球菌（18/24；75.0%）和表皮葡萄球菌菌株（20/33；60.6%）中最常检测到的基因都是eno。在金黄色葡萄球菌和表皮葡萄球菌菌株中均检测到icaAB和ebpS基因，这些菌株之间的相似性分别为12.5% - 15.1%和4.2% - 6.0%。bap仅在表皮葡萄球菌中检测到（3.0%）。使用卡方检验对生物膜形成水平进行统计学比较。生物膜检测的两种方法CRA和MTP之间在生物膜形成量上没有统计学显著差异（p>0.05）。在显著性水平α = 0.05时，对所有六个监测参数的比较表明，所测试的金黄色葡萄球菌和表皮葡萄球菌菌株的特征之间没有相关性。证实了从57例绵羊临床乳腺炎病例中分离出的细菌能形成生物膜。CRA方法对金黄色葡萄球菌的敏感性和特异性分别为94.44%和66.66%，对表皮葡萄球菌分别为92.0%和87.5%。CRA和MTP方法均可推荐用于检测从患有临床乳腺炎的绵羊乳汁中分离出的金黄色葡萄球菌和表皮葡萄球菌菌株的生物膜产生情况。
