Detection of slime production by means of an optimised Congo red agar plate test based on a colourimetric scale in Staphylococcus epidermidis clinical isolates genotyped for ica locus
Detection of slime production by means of an optimised Congo red agar plate test based on a colourimetric scale in Staphylococcus epidermidis clinical isolates genotyped for ica locus
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DOI：
10.1016/s0142-9612(02)00171-0
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发表时间：
2002-11-01
期刊：
影响因子：
14
通讯作者：
Montanaro, L
中科院分区：
文献类型：
--
作者：
Arciola, CR;Campoccia, D;Montanaro, L
对113株S.表皮葡萄球菌菌株分离出前生物材料相关感染。通过PCR方法检测所有菌株中负责粘液合成的icaA和icaD基因的存在，并通过刚果红琼脂（CRA）平板试验检测体外粘液产生能力。在本研究中，采用六色参考标度对原始CRA测试进行优化，用于菌落颜色的精细分类。量表的六种色调如下：极黑（v B）、黑色（B）、几乎黑色（ab），被认为是阳性结果，波尔多（brd）、红色（r）和极红（vr），被解释为阴性。57.5%的菌株为icaA、icaD阳性的Lis，并能在CRA上形成粘液，菌落颜色为v B（35.4%），B（15.9%）：ab（6.2%）。icaA、icaD阴性菌株占42.5%，CRA均阴性：brd（19.5%）、r（14.2%）、vr（8.8%）。颜色分类与伊卡基因信息的比较证实了所采用量表的有效性，为CRA试验执行期间正确解释菌落颜色所用的标准提供了支持。总的来说，这些结果表明这两种实验方法之间的良好一致性和CRA板测试的良好可靠性，特别是当这是由色度尺度支持时。(C)2002爱思唯尔科技有限公司。保留所有权利。
This investigation was conduced on a collection of 113 S. epidermidis strains isolated front biomaterial-associated infections. All strains were examined both for the presence of icaA and icaD genes responsible for slime synthesis by a PCR method and for the in vitro slime production ability by the Congo red agar (CRA) plate test. In the present study, the original CRA test was optimised adopting a six-colour reference scale for a fine classification of colonies colours. The six-colour tones of the scale were Lis follows: very black (vb), black (b), almost black (ab), which were considered as positive results, and bordeaux (brd), red (r), and very red (vr), interpreted as negative. 57.5% of all the strains were found to be icaA icaD-positive Lis well as slime-forming onto CRA, exhibiting the following colonies colours: vb (35.4%) b (15.9%): ab (6.2%). The percentage of icaA icaD-negative strains was 42.5% and all of them were negative onto CRA: brd (19.5%), r (14.2%), vr (8.8%). The comparison of colour classification with the information on ica genes confirmed the validity of the scale adopted, providing Support to the criteria used for a correct interpretation of the colonies colour during the execution of the CRA test. Overall these results indicate a fine consistency between these two experimental methods and a good reliability of CRA plate test, especially when this is supported by a colourmetric scale. (C) 2002 Elsevier Science Ltd. All rights reserved.