Institute of Medical Microbiology and Hygiene, University Hospital of Regensburg, Regensburg, Germany.
Euro Surveill. 2009 Dec 10;14(49):19436.
A number of real-time PCR assays for direct detection of methicillinresistant (MRSA) in clinical specimens are targeting staphylococcal cassette chromosome mec (SCCmec) right extremity sequences and the S. aureus chromosomal orfX gene sequences located to the right of the SCCmec integration site. When testing 184 MRSA strains of human and animal origin from geographically distinct locations, we identified several characteristic single-nucleotide polymorphisms (SNPs) within the SCCmec-orfX junction of livestock-associated (LA) MRSA CC398 which serve as suitable strain markers for screening purposes. Within an assay time of 60 minutes and an additional 10 minutes for the melting curve analysis, all MRSA CC398 isolates were correctly identified by their characteristic T(m) value in the commercial LightCycler MRSA Advanced test. Studies to confirm the diagnostic accuracy of the SNP-based strain identification assay with a larger collection of clinical and LA-MRSA strains are ongoing.
许多用于直接检测临床标本中耐甲氧西林金黄色葡萄球菌（MRSA）的实时 PCR 检测方法针对的是葡萄球菌盒式染色体 mec（SCCmec）的右侧末端序列，以及位于 SCCmec 整合位点右侧的金黄色葡萄球菌染色体 orfX 基因序列。在对来自地理位置不同的人和动物来源的 184 株 MRSA 菌株进行检测时，我们在与牲畜相关（LA）MRSA CC398 的 SCCmec-orfX 连接处发现了几个特征性的单核苷酸多态性（SNP），这些 SNP 可作为筛选目的的合适菌株标记。在 60 分钟的检测时间内，通过额外的 10 分钟熔解曲线分析，所有 MRSA CC398 分离株都可以通过其在商用 LightCycler MRSA Advanced 检测中的特征 T(m)值被正确识别。正在进行研究，以用更大的临床和 LA-MRSA 菌株集合来确认基于 SNP 的菌株鉴定检测的诊断准确性。
