A Comparison of Genotypic and Phenotypic Methods for Analyzing the Susceptibility to Sulfamethoxazole and Trimethoprim in Edwardsiella piscicida
A Comparison of Genotypic and Phenotypic Methods for Analyzing the Susceptibility to Sulfamethoxazole and Trimethoprim in Edwardsiella piscicida
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DOI：
10.1089/mdr.2017.0137
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发表时间：
2018-02-13
影响因子：
2.6
通讯作者：
Smith, Peter
中科院分区：
文献类型：
--
作者：
Kim, Ahran;Lim, Yunjin;Smith, Peter
在对来自韩国水产养殖场的39个杀鱼爱德华氏菌菌株的研究中，在16个菌株中检测到sul基因，在19个菌株中检测到dfr基因。10个分离株同时含有sul和dfr基因。进行MIC和纸片扩散区测定以测量39个分离株的表型亲和性。将标准化耐药性解释应用于这些数据，以将分离株分类为完全敏感或表现为敏感性降低。标准CLSI方案规定在MIC和纸片扩散试验中使用磺胺甲恶唑/甲氧苄啶（20：1）的混合物。使用CLSI MIC方案，100%含有dfr基因的分离株，但仅75%含有sul基因的分离株被归类为表现出敏感性降低。使用CLSI纸片扩散方案，仅58%的含有dfr基因的分离株和69%的含有sul基因的分离株被归类为表现出敏感性降低。当在MIC和纸片扩散方案中用单一药物甲氧苄啶替代组合混合物时，100%的dfr阳性分离株被归类为NWT。当单药磺胺甲恶唑被取代，MIC的分析特征为100%和光盘区数据94%的磺阳性分离株表现出降低的敏感性。有人认为，使用甲氧苄啶和磺胺甲恶唑作为单一药物在表型敏感性试验将提供更有意义的数据比目前推荐使用这两种药物的组合。
In a study of 39 isolates of Edwardsiella piscicida made from Korean aquaculture sites, sul genes were detected in 16 isolates and dfr genes in 19. Ten isolates were shown to contain both sul and dfr genes. MIC and disc diffusion zones assays were performed to measure the phenotypic susceptibilities of the 39 isolates. Normalized resistance interpretation was applied to these data to categorize isolates as either fully susceptible or as manifesting reduced susceptibility. The standard CLSI protocols specify the use of a mixture of sulfamethoxazole/trimethoprim (20:1) in both MIC and disc diffusion tests. Using the CLSI MIC protocol, 100% of the isolates containing dfr genes, but only 75% of the isolates containing sul genes, were categorized as manifesting reduced susceptibility. Using the CLSI disc diffusion protocol, only 58% of the isolates containing dfr genes and 69% of those containing sul genes were categorized as manifesting reduced susceptibility. When the single agent trimethoprim was substituted for the combined mixture in both the MIC and disc diffusion protocols, 100% of the dfr-positive isolates were categorized as NWT. When the single-agent sulfamethoxazole was substituted, the analysis of the MIC characterized 100% and the disc zone data 94% of the sul-positive isolates as manifesting reduced susceptibility. It is argued that the use of trimethoprim and sulfamethoxazole as single agents in phenotypic susceptibility tests would provide more meaningful data than the currently recommended use of these two agents combined.