Tesch W, Ryffel C, Strässle A, Kayser F H, Berger-Bächi B
Institute of Medical Microbiology, University of Zurich, Switzerland.
Antimicrob Agents Chemother. 1990 Sep;34(9):1703-6. doi: 10.1128/AAC.34.9.1703.
A region was identified on the methicillin resistance determinant (mec) isolated from Staphylococcus epidermidis and cloned into Staphylococcus carnosus which was responsible for a novel downregulation of the expression of methicillin resistance. The presence of this region reduced the overall expression of methicillin resistance and the synthesis of the mec-encoded penicillin-binding protein 2' (PBP 2') in S. carnosus. This region was located by Bal31 deletion mutagenesis upstream of the structural gene for PBP 2'. Deletions within this region resulted in higher levels of expression of methicillin resistance and increased levels of PBP 2' synthesis. We tentatively called this region mecR. Analysis of selected Mcr strains of Staphylococcus aureus and S. epidermidis by Southern hybridization suggested that the natural occurrence of two types of mec resistance determinants differ by the presence or absence of mecR-specific sequences.
在从表皮葡萄球菌分离出的耐甲氧西林决定簇（mec）上鉴定出一个区域，并将其克隆到肉葡萄球菌中，该区域导致了耐甲氧西林表达的一种新型下调。该区域的存在降低了肉葡萄球菌中耐甲氧西林的总体表达以及mec编码的青霉素结合蛋白2'（PBP 2'）的合成。通过Bal31缺失诱变将该区域定位在PBP 2'结构基因的上游。该区域内的缺失导致耐甲氧西林表达水平升高和PBP 2'合成水平增加。我们暂时将该区域称为mecR。通过Southern杂交对金黄色葡萄球菌和表皮葡萄球菌的选定Mcr菌株进行分析表明，两种类型的mec耐药决定簇的自然存在因是否存在mecR特异性序列而有所不同。
