Kehrenberg Corinna, Meunier Danièle, Targant Hayette, Cloeckaert Axel, Schwarz Stefan, Madec Jean-Yves
Institut für Tierzucht, Bundesforschungsanstalt für Landwirtschaft (FAL) Höltystr. 10, 31535 Neustadt-Mariensee, Germany.
J Antimicrob Chemother. 2006 Jul;58(1):13-7. doi: 10.1093/jac/dkl174. Epub 2006 May 2.
A florfenicol-resistant Pasteurella trehalosi isolate from a calf was investigated for the presence and the location of the gene floR.
The P. trehalosi isolate 13698 was investigated for its in vitro susceptibility to antimicrobial agents and its plasmid content. A 14.9 kb plasmid, designated pCCK13698, was identified by transformation into Pasteurella multocida to mediate resistance to florfenicol, chloramphenicol and sulphonamides. The plasmid was sequenced completely and analysed for its structure and organization.
Plasmid pCCK13698 exhibited extended similarity to plasmid pHS-Rec from Haemophilus parasuis including the region carrying the parA, repB, rec and int genes. Moreover, it revealed similarities to plasmid RSF1010 in the parts covering the mobC and repA-repC genes and to plasmid pMVSCS1 in the parts covering the sul2-catA3-strA gene cluster. Moreover, the floR gene area corresponded to that of transposon TnfloR. In addition, two complete insertion sequences were detected that were highly similar to IS1593 from Mannheimia haemolytica and IS26 from Enterobacteriaceae. Several potential recombination sites were identified that might explain the development of plasmid pCCK13698 by recombination events.
The results of this study showed that in the bovine pathogen P. trehalosi, floR-mediated resistance to chloramphenicol and florfenicol was associated with a plasmid, which also carried functionally active genes for resistance to sulphonamides (sul2) and chloramphenicol (catA3). This is to the best of our knowledge the first report of resistance genes in P. trehalosi and only the second report of the presence of a florfenicol-resistance gene in target bacteria of the family Pasteurellaceae.
对一株从犊牛分离得到的耐氟苯尼考的海藻糖巴氏杆菌进行研究，以确定floR基因的存在及位置。
研究海藻糖巴氏杆菌分离株13698对抗菌药物的体外敏感性及其质粒含量。通过转化多杀性巴氏杆菌鉴定出一个14.9 kb的质粒，命名为pCCK13698，该质粒介导对氟苯尼考、氯霉素和磺胺类药物的耐药性。对该质粒进行全序列测序，并分析其结构和组织。
质粒pCCK13698与副猪嗜血杆菌的质粒pHS-Rec具有广泛的相似性，包括携带parA、repB、rec和int基因的区域。此外，在覆盖mobC和repA-repC基因的部分与质粒RSF1010相似，在覆盖sul2-catA3-strA基因簇的部分与质粒pMVSCS1相似。此外，floR基因区域与转座子TnfloR的区域相对应。另外，检测到两个完整的插入序列，它们与溶血曼氏杆菌的IS1593和肠杆菌科的IS26高度相似。鉴定出几个潜在的重组位点，这可能解释了质粒pCCK13698通过重组事件的产生。
本研究结果表明，在牛病原体海藻糖巴氏杆菌中，floR介导的对氯霉素和氟苯尼考的耐药性与一个质粒有关，该质粒还携带对磺胺类药物（sul2）和氯霉素（catA3）耐药的功能活性基因。据我们所知，这是海藻糖巴氏杆菌耐药基因的首次报道，也是巴斯德菌科目标细菌中氟苯尼考耐药基因存在的第二篇报道。
