Kraft C A, Timbury M C, Platt D J
Epidemiol Infect. 1987 Jun;98(3):241-52. doi: 10.1017/s0950268800061999.
Restriction enzyme fingerprinting was applied to 72 transferable trimethoprim resistance plasmids to examine aspects of their epidemiology and molecular relatedness. These plasmids had previously been divided into 25 groups according to differences in mol. wts and in antimicrobial resistance determinants. Restriction enzyme fingerprinting allowed the plasmids to be further divided into 44 different groups. The groups based on molecular weight and resistance patterns often, but not invariably, corresponded with those based on restriction enzyme fingerprints. Some plasmids with the same mol. wt and resistance pattern had different digest fingerprints and conversely, although more rarely, plasmids which differed in molecular weight by as much as 10 MDa or in resistance pattern by one resistance marker, had indistinguishable fingerprints. The plasmids were initially divided into three broad categories according to which restriction enzymes gave fingerprints of 6-20 fragments. These categories differed in the molecular weights of the plasmids contained, the numbers of resistance markers, and the proportions of the plasmids which carried transposon Tn7. Some plasmids were more widespread and persistent than others with the same mol. wt and resistance pattern but with a different restriction enzyme fingerprint. Thus, application of this technique has shown the trimethoprim resistance plasmids studied to be more diverse than was indicated by determination of mol. wt and resistance pattern, and has indicated changes in the plasmid pool over the 3 years during which they were collected.
限制性内切酶指纹图谱技术被应用于72个可转移的甲氧苄啶耐药质粒，以研究其流行病学及分子相关性。这些质粒先前已根据分子量和抗微生物耐药决定簇的差异被分为25组。限制性内切酶指纹图谱技术可将这些质粒进一步分为44个不同的组。基于分子量和耐药模式划分的组通常（但并非总是）与基于限制性内切酶指纹图谱划分的组相对应。一些分子量相同且耐药模式相同的质粒具有不同的酶切指纹，反之，尽管较为少见，但分子量相差多达10 MDa或耐药模式相差一个耐药标记的质粒却具有难以区分的指纹。根据产生6 - 20条片段指纹的限制性内切酶，这些质粒最初被分为三大类。这些类别在所含质粒的分子量、耐药标记数量以及携带转座子Tn7的质粒比例方面存在差异。一些质粒比其他分子量相同、耐药模式相同但限制性内切酶指纹不同的质粒分布更广且更持久。因此，该技术的应用表明，所研究的甲氧苄啶耐药质粒比通过分子量和耐药模式测定所显示的更为多样，并表明在收集它们的3年期间质粒库发生了变化。
