3种亚抑菌浓度抗生素对耐药基因水平传播的影响

The effect of resistance genes horizontal transfer under stimulation of subinhibitory concentrations of antibiotics

目的揭示在不同种类的亚抑菌浓度抗生素作用下,细菌耐药基因水平传播的一般规律。方法选择四种不同抑菌机制的抗生素(氨苄西林、环丙沙星、红霉素和链霉素),在亚抑菌浓度条件下,将供体菌和受体菌共培养,通过PCR法和整合效率的测定,研究了整合酶对耐药基因整合效率的变化规律,并使用了不同耐药基因进行验证。结果除红霉素外,在低于50%MIC浓度抗生素的作用下,随着抗生素作用剂量的提高,整合酶整合效率有增高的趋势。结论亚抑菌浓度的抗生素作用下,提高了整合酶的整合效率,能够促进耐药基因的水平传播。

Objective To reveal the general pattern of resistance genes horizontal transfer, under the stimulation of antibiotics with subinhibitory concentrations. Methods Four kinds of antibiotics were chosen, for example, ampicillin, ciprofloxacin, erythromycin and streptomycin, which represent different antibacterial mechanism. The minimum inhibitory concentrations of the donor and the receptor bacteria were firstly tested. The variations of integration efficiency of the donor and receptor were studied under stimulation of subinhibitory concentrations of antibiotics. The four kinds of resistance gene cassettes （dfrA1, aadA1, aadB and cmlA） were used for verification. Results Except erythromycin, other three antibiotics raised the integration efficiency in a dose-dependent manner under the stimulation of antibiotics with subinhibitory concentrations below 50% MIC. Four kinds of resistance genes presented the same pattern. The integration efficiency under stimulation of ciprofloxacin was the highest among the four kinds of antibiotics. Conclusion The integration efficiency can be raised under of the subinhibitory concentrations antibiotics stimulation.