Kreiswirth B, Kornblum J, Arbeit R D, Eisner W, Maslow J N, McGeer A, Low D E, Novick R P
Bureau of Laboratories, New York City Department of Health, NY 10016.
Science. 1993 Jan 8;259(5092):227-30. doi: 10.1126/science.8093647.
Soon after methicillin was introduced into clinical practice in the early 1960s, resistant strains of Staphylococcus aureus (MRSA) appeared, bearing a newly acquired resistance gene, mecA, that encodes a penicillin binding protein, PBP2a. MRSA have spread throughout the world, and an investigation of the clonality of 472 isolates by DNA hybridization was performed. All 472 isolates could be divided into six temporally ordered mecA hybridization patterns, and three of these were subdivided by the chromomosomal transposon Tn554. Each Tn554 pattern occurred in association with one and only one mecA pattern, suggesting that mecA divergence preceded the acquisition of Tn554 in all cases and therefore that mecA may have been acquired just once by S. aureus.
20世纪60年代初甲氧西林引入临床实践后不久，耐甲氧西林金黄色葡萄球菌（MRSA）菌株就出现了，它携带一个新获得的耐药基因mecA，该基因编码一种青霉素结合蛋白PBP2a。MRSA已传播至全球，并且通过DNA杂交对472株分离株的克隆性进行了调查。所有472株分离株可分为六种按时间顺序排列的mecA杂交模式，其中三种又被染色体转座子Tn554细分。每种Tn554模式都与一种且仅一种mecA模式相关联，这表明在所有情况下mecA分化都先于Tn554的获得，因此mecA可能仅被金黄色葡萄球菌获得过一次。
