High-level quinolone resistance require mutations in both DNA gyrase gene and topoisomerase Ⅳ gene. ② Bacterial cell wall is the barrier for the entry of antibiotics. 高水平的耐药由DNA回旋酶和拓扑异构酶Ⅳ同时发生变异造成。② 细菌细胞壁是抗生素进入的屏障。
Topoisomerases are enzymes that regulate the overwinding or underwinding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure. During DNA replication and transcription, DNA becomes overwound ahead of a replication fork. If left unabated, this torsion would eventually stop the ability of RNA & DNA polymerase involved in these processes to continue down the DNA strand.