Approximately 15–20% of the S. aureus genome contains mobile genetic elements that can cause discrepancies between phenotypic and genotypic identification methods. Three blood culture bottles (each from a different patient) that showed discordant results, were shown to contain 2 S. aureus isolates after additional subcultures. One bottle had MRSA and MSSA that by DNA sequence analysis differed only by 31 kb; however, the deletions encompassed parts of SCCmec including mecA and SCC_M1. The second bottle contained MRSA and MSSA that differed by 124 kb; the MSSA was missing the entire SCCmec and spa regions. The last bottle contained 2 MRSA, one with ACME II disrupting SCCmec and a 24 bp spa deletion. The deletions in SCCmec and the other elements gave rise to the discrepancies between molecular and the original culture results. Such discrepancies should prompt a search for additional strains in the blood culture bottle.

金黄色葡萄球菌基因组中约有15–20％包含可导致表型和基因型识别方法差异的流动遗传元件。结果显示不一致的三个血液培养瓶（每个来自不同的患者）显示在另外的亚培养后包含2个金黄色葡萄球菌分离株。一瓶MRSA和MSSA的DNA序列分析相差仅31 kb；然而，缺失涵盖了SCC mec的部分，包括mecA和SCC _M1。第二瓶含有MRSA和MSSA，相差124 kb；MSSA缺少整个SCC mc和spa地区。最后一瓶含有2个MRSA，一个带有ACME II破坏SCC mec和一个24 bp的spa缺失。SCC mec和其他元素的缺失导致分子结果与原始培养结果之间的差异。这种差异应促使在血培养瓶中寻找其他菌株。