分析了4种常见的喹诺酮类抗生素(QNs)对发光菌(Photobacterium phosphoreum)的单一毒性和等毒性比例下的联合毒性作用,基于毒性单位法(TU)、相加指数法(AI)和混合毒性指数法(MTI)评价混合体系联合毒性的作用类型.加替沙星、洛美沙星、左氧氟沙星和诺氟沙星4种喹诺酮类医药品对发光菌的半数效应浓度(EC50)分别为:0.084× 10-3、0.137×10-3、0.129×10-3和0.151×10-3 mol·L-1.不同的评价方法对4种QNs的联合效应评价结果具有较好的一致性,多元混合体系呈现为不同程度的拮抗作用.结合分子结构特征和不同取代基相互作用,初步分析了联合毒性机理,进一步的毒性作用机制还需通过对生物生理生化反应等进行深入研究.本研究多种QNs混合体系呈现拮抗作用为主,揭示了此类医药品在环境中的联合使用可能导致药效降低以及微生物耐药性的产生和传播.%The single toxicity and joint toxicity under the same toxicity ratio of four quinolones (QNs) were studied to Photosbacterium phosphoreum.The action types of joint toxicity were evaluated by toxicity unit (TU),additive index (AI) and mixtures toxicity index (MTI).The acute toxicity EC50 of gatifloxacin,lomefloxacin,levofloxacin and norfloxacin to Photosbacterium phosphoreum were 0.084 × 10-3,0.137 × 10-3,0.129 × 10-3 and 0.151 × 10-3 mol · L-1 respectively.The results of three evaluating methods were in agreement,and the results suggested that the antagonisms of various extents existed among the multi-mixture systems.Mechanisms of joint toxicity were preliminary analyzed by characteristics of quinolones molecular structure and interaction of different substituent.The further mechanism of toxicity action need further understanding on exploring physiological and biochemical reaction of organisms.The facts that quinolone mixture systems showed almost antagonism reveal joint toxicity in the environment may induce the generation of antibiotic resistance and its spread.
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