Hashimoto Y, Tanimoto K, Ozawa Y, Murata T, Ike Y
Department of Microbiology, Gunma University School of Medicine, Showa-machi 3-39-22, Maebashi, Gunma, Japan.
FEMS Microbiol Lett. 2000 Apr 15;185(2):247-54. doi: 10.1111/j.1574-6968.2000.tb09070.x.
The vancomycin-resistant enterococci GV1, GV2 and GV3, which were isolated from droppings from broiler farms in Japan have been characterized as VanA-type VRE, which express high-level vancomycin resistance (256 or 512 microg ml(-1), MIC) and low-level teicoplanin resistance (1 or 2 microg ml(-1), MIC). The vancomycin resistances were encoded on plasmids. The vancomycin resistance conjugative plasmid pMG2 was isolated from the GV2 strain. The VanA determinant of pMG2 showed the same genetic organization as that of the VanA genes encoded on the representative transposon Tn1546, which comprises vanRSHAXYZ. The nucleotide sequences of all the genes, except the gene related to the vanS gene on Tn1546, were completely identical to the genes encoded on Tn1546. Three amino acid substitutions in the N-terminal region of the deduced VanS were detected in the nucleotide sequence of vanS encoded on pMG2. There were also three amino acid substitutions in the vanS gene of the GV1 and GV3 strains in the same positions as in the vanS gene of pMG2. Vancomycin induced the increased teicoplanin resistance in these strains.
从日本肉鸡场粪便中分离出的耐万古霉素肠球菌GV1、GV2和GV3已被鉴定为VanA型耐万古霉素肠球菌，它们表现出高水平的万古霉素耐药性（256或512μg/ml，MIC）和低水平的替考拉宁耐药性（1或2μg/ml，MIC）。万古霉素耐药性由质粒编码。从GV2菌株中分离出了耐万古霉素接合质粒pMG2。pMG2的VanA决定簇与代表性转座子Tn1546上编码的VanA基因具有相同的基因结构，Tn1546包含vanRSHAXYZ。除了与Tn1546上vanS基因相关的基因外，所有基因的核苷酸序列与Tn1546上编码的基因完全相同。在pMG2编码的vanS核苷酸序列中，推导的VanS的N端区域检测到三个氨基酸替换。在GV1和GV3菌株的vanS基因中，与pMG2的vanS基因相同位置也有三个氨基酸替换。万古霉素诱导这些菌株中替考拉宁耐药性增加。
