孙硕　吕世明　谭艾娟　华夏　李博岩　焦亚琴

摘 要：通过测定野生型大肠杆菌对氟喹诺酮类药物敏感的、耐药的以及从耐药诱导恢复敏感的3种菌株的生长曲线，探讨适应度代价对细菌耐药性变化的影响。结果表明：对氟喹诺酮类药物耐药的大肠杆菌C02的生长速率远低于敏感菌株C01和恢复敏感性后菌株C03； 而敏感菌株C01和敏感性恢复菌株C03的细菌生长曲线相近，说明在无药物选择压力环境中，适应度代价高的耐药菌生存竞争力低于适应度代价低的敏感菌，敏感菌逐渐取代耐药菌，使菌群对药物的敏感性得以恢复。

关键词：大肠杆菌；氟喹诺酮类药物；适合度代价；生长曲线；敏感性恢复

中图分类号：R378.2+1 文献标识码：A DOI 编码：10.3969/j.issn.1006-6500.2016.04.008

Abstract： To discuss the effect of the fitness cost on drug-resistanc reversal of Escherichia coli， the growth curves of three strains E.coli， which E. coli C01 was sensitivity to fluoroquinolones， E. coli C02 was resistance to fluoroquinolones and E. coli C03 was restored sensitivity to fluoroquinolones， were determined. The result showed that the growth velocity of E. coli C02 resistented to fluoroquinolones was far lower than E. coli C01 or E. coli C03， and the growth velocities of E. coli C01 or E. coli C03 were quit similar. It demonstated that the survival competitiveness of drug-resistant bacteria possessed the high fitness cost was lower than sensitive one armied low fitness cost in the environment of no drug selection pressure. The drug-resistant bacteria was gradually replaced by ensitive bacteria and the drug sensitivity of microbiome was restored.

Key words： Escherichia coli； fluoroquinolones； fitness cost； growth curve； sestore sensitivity

细菌耐药性是现代医学所面临的一大重要难题，近几年的统计发现细菌的耐药率呈现普遍上升趋势[1-2]。在养殖业中抗菌药物的不规范用药，导致动物源细菌耐药水平不断升高，对养殖业健康发展构成严重威胁，并增加了动物性食品的不安全性[3]，因此，探索降低或消除细菌耐药性已经成为当前研究的热点。研究表明，高度耐药的沙门氏菌在没有药物选择压力的环境中其适合度代价将升高[4]，其生长竞争力低于敏感菌，使得敏感菌成为优势菌群，最终取代耐药菌而恢复对药物的敏感性。故养殖场可通过停止使用某种抗菌药物来恢复细菌对该药物的敏感性[5]。本研究通过测定对耐氟喹诺酮类药物不同耐药状态大肠杆菌的生长曲线，考察对氟喹诺酮类药物耐药大肠杆菌生存适合度代价在细菌耐药性恢复上的作用，为养殖场制定合理的轮换用药方案，降低细菌耐药性的危害提供支持。……