高度耐药嗜水气单胞菌的定向诱导及其交叉耐药性分析

为了分析比较不同抗生素对耐药嗜水气单胞菌(Aeromonas hydrophila)的诱导效率,从五大类抗生素中各挑选出一种代表性的抗生素,在针对嗜水气单胞菌菌株AH10的防耐药突变浓度(mutant prevention concentration,MPC)的琼脂平板上,分别筛选出五株耐药菌株,并对筛选的耐药菌株进行交叉耐药性分析,制定出这些耐药菌株对常用抗生素的最小抑菌浓度(minimal inhibitory concentrations,MIC)图谱。结果显示:四环素、氟苯尼考、磺胺嘧啶、硫酸新霉素、诺氟沙星对AH10的MIC分别为:1.0、0.5、8.0、8.0、0.25μg/m L;MPC分别为4.0、3.0、128、88、2.0μg/m L,分离的耐药菌株对所使用抗生素的MIC均提高100倍以上。4℃划线平板冰箱保存条件下,一个月内个别耐药菌株耐药性下降。在药物筛选压力下,菌株耐药性随着传代次数增多而表现出递增的趋势。同属一类抗生素耐药相关性较高;不同大类抗生素压力下筛选出来的耐药菌株表现出不同的交叉耐药性。

Directional induction of antibiotics-resistant Aeromonas hydrophila and analysis of its multiple drug resistance

In order to compare the effects of available antibiotics on inducing drug-resistant A. hydrophila and lay a founda-tion for rational use of different antibiotics, five typical antibiotics drugs representing the five major categories of antibiotics were selected to induce drug-resistant A. hydrophila strain AH10 on agar plate supplied with a concentration of mutant pre-vention concentration ( MPC ) for each specific antibiotics. Through determining the minimum inhibitory concentration ( MIC) of different antibiotics on all the identified drug-resistant mutant bacterial, the cross drug-resistance map was drawn in this report. The results showed that the MIC of Tetracycline, Florfenicol, Sulfadiazine, Neomycin sulfate and Norfloxa-cin to AH10 was 1. 0, 0. 5, 8. 0, 8. 0, and 0. 25 μg/mL, respectively; the corresponding MPC value was 4. 0, 3. 0, 128, 88 and 2. 0μg/mL, respectively. Generally, induced drug-resistant bacteria demonstrated an over 100 times-higher MIC value in comparison to the wild type of A. hydrophila strain AH10. Individual strain resistance decreased after storage at 4 ℃ in one month. Under the pressure of drug screening, the resistance of the strains increased with the increase of passages. Resistant mutants induced from antibiotics belonging to the same class drug-resistant correlation is higher while, resistant mutants induced from antibiotics belonging to different classes demonstrated different resistant map.