加替沙星对金黄色葡萄球菌的体外抗菌活性

考察加替沙星对金黄色葡萄球菌的体外抗菌活性以及抗MRSA的能力。采用药敏纸片法（K－B法），从129株临床分离的金黄色葡萄球菌筛选对甲氧西林和氟喹诺酮类药物的耐药菌株，用琼脂二倍稀释法对交叉耐药菌进行MIC测试，比较了加替沙星与环丙沙星等第二代氟喹诺酮类药物的耐药菌株，用琼脂二倍稀释法对交叉耐药菌进行MIC测试，比较了加替沙星与环丙沙星等第二代氟喹诺酮类药物的抗菌活性。用苯唑西林筛选三代自发突变株，比较环丙沙星、加替沙星对MRSA的抗菌活性。实验表明，苯唑西林、环丙沙星、氧氟沙星、左氧氟沙星对129株金黄色葡萄球菌的耐药率相似。体外活性表明，加替沙星比环丙沙星等第二代氟喹诺酮类药物的抗菌活性强，抗MRSA菌株的活性较强；敏感金黄色葡萄球菌发生加替沙星耐药的突变频率在所试药物中也是最低的。说明加替沙星比环丙沙星等第二代氟喹诺酮类药物的抗菌活性得到明显提高。

In vitro antibacterial activity of gatifloxacin against S. aureus

The activities of gatifloxacin against Staphylococcus aureus , especially against methicillin resistant S.aureus were investigated. Disc agar dilution was adopted to select methicillin/fluoroquinolone susceptible and resistant clinical isolates of S.aureus . The MICs of 44 cross resistant strains were determined by agar dilution assay method; the activity of gatifloxacin was compared with ciprofloxacin and other quinolones; the isolation of spontaneous MRSA mutants was obtained by increasing two fold concentrations of oxacillin. The activities of gatifloxacin and ciprofloxacin against the MRSA were also determined. The results indicated that the activity of gatifloxacin was more potent than the other fluoroquinolones. Gatifloxacin also showed potent activity against the MRSA. The emerging frequency of gatifloxacin resistant mutation was lower than ciprofloxacin. This result indicated that gatifloxacin could improve the activity against Staphylococcus aureus , especially against methicillin resistant S. aureus compared with the other second generation fluoroquinolone.