Maseda H, Saito K, Nakajima A, Nakae T
Department of Molecular Life Science, Tokai University School of Medicine, 259-1193, Isehara, Japan.
FEMS Microbiol Lett. 2000 Nov 1;192(1):107-12. doi: 10.1111/j.1574-6968.2000.tb09367.x.
We found three variations of wild-type strains in terms of mexT-mediated regulation of the MexEF-OprN efflux pump, in which overexpression of the pump results in nfxC-type antibiotic resistance in Pseudomonas aeruginosa. Type-I: the mexT gene of the wild-type strain encoded inactive MexT and the nfxC-type mutants derived from this parent had an additional mutation in mexT converting MexT from the inactive to the active form. Type-II: The mexT gene in the wild-type strain had an 8-bp insert producing inactive MexT and the nfxC-type mutants from this parent had a deletion of the 8-bp insert converting inactive MexT to the active form. Type-III: Both the wild-type strain and its nfxC-type derivative produced identical and active MexT. The nfxC mutant from this parent must have an additional mutation. The original nfxC mutant isolated in 1990 might be derived from the Type-I parent strain.
我们发现野生型菌株在mexT介导的MexEF - OprN外排泵调控方面存在三种变体，其中该泵的过表达会导致铜绿假单胞菌产生nfxC型抗生素耐药性。I型：野生型菌株的mexT基因编码无活性的MexT，源自该亲本的nfxC型突变体在mexT中有一个额外突变，使MexT从无活性形式转变为活性形式。II型：野生型菌株中的mexT基因有一个8 bp的插入片段，产生无活性的MexT，源自该亲本的nfxC型突变体有一个8 bp插入片段的缺失，使无活性的MexT转变为活性形式。III型：野生型菌株及其nfxC型衍生物均产生相同且有活性的MexT。源自该亲本的nfxC突变体必定有一个额外突变。1990年分离出的原始nfxC突变体可能源自I型亲本菌株。
