畜牧兽医学报2011，Vol.42Issue(1)：71-76,6.
氟喹诺酮类抗茵药对临床分离猪链球菌的防耐药变异浓度测定及一步耐药突变株的筛选
Mutant Prevention Concentrations of Fluoroquinolones for Clinical Isolates of Streptococcus suis and Screen of Single-step Resistant Mutants
摘要
Abstract
The mutant prevention concentration (MPC) represents a threshold above which the selective proliferation of resistant mutants is expected to occur only rarely. Measurement of the minimal inhibitory concentration (MIC) and the MPC for 32 veterinary clinical strains of Streptococcus suis revealed that ofloxacin and enrofloxacin are more potent than ciprofloxacin and peflox-acin mesylate to restrict the selective enrichment of resistant mutants. Based on their potential for restricting the selection of resistant mutants, the four fluoroquinolones, in descending order, were found to be enrofloxacin > ofloxacin> ciprofloxacin > pefloxacin mesylate. For several compounds, all of the clinical isolates lacked a known resistance mutation in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC and parE. Additionally, the isolates were tested for CCCP or reserpine-sensitive efflux. The MICs of ciprofloxacin, enrofloxacin, ofloxacin and pefloxacin mesylate for each single-step mutants were determined by agar dilution on Mueller-Hinton agar plates plus 5% sheep blood in the presence and absence of CCCP (40mg ·L-1) or reserpine (50 mg · L-1 ). As a result, isolates showed no reduction in MIC in the presence of CCCP and considered negative for CCCP-sensitive efflux. Nevertheless, it revealed a four or more-fold decrease of ciprofloxacin accumulation in the presence of reserpine in the ciprofloxacin first-step mutants compared to that in the parent resistant strain, and it s considered that there is a reserpine-sensitive efflux to decrease the level of ciprofloxacin accumulation in singlestep mutants.关键词
氟喹诺酮类抗菌药/猪链球菌/MIC/MPC/耐药突变株/主动外排泵Key words
fluoroquinolone/Streptococcus suis/MIC/ MPC/single-step resistant mutants/ active efflux pump分类
基础医学引用本文复制引用
张雨菡,王丽平,陆承平..氟喹诺酮类抗茵药对临床分离猪链球菌的防耐药变异浓度测定及一步耐药突变株的筛选[J].畜牧兽医学报,2011,42(1):71-76,6.基金项目
国家自然科学基金(30972220) （30972220）
公益性行业(农业)科研专项(200803016) （农业）
