水产动物常见病原菌的耐药性分析及中草药体外抑菌活性的检测

Drug resistance analysis of common pathogens of aquatic animals and bacteriostasis activity assay of Chinese herb medicine in vitro

目的了解安徽省水产动物常见病原菌的耐药现状和耐药机制，探讨27种单味中草药和5个中草药复方配伍对耐药菌株的体外抑菌活性。方法分别采用K—B纸片琼脂扩散法和双纸片增效法检测常见病原菌的耐药性和ESBLs，同时使用平板打孔法和改良微量稀释法检测中草药的体外抑菌活性。结果4种常见病原菌的23个分离株对常用的5类抗生素均呈现不同程度的耐药性，其中铜绿假单胞菌的耐药谱最广，对14种抗生素的耐药率均为100％。供试菌中仅检出2株铜绿假单胞菌为产ESBLs株，检出率为8．69％。黄连、大黄、金银花、夏枯草、地锦草、丹皮、马齿苋和连翘8种中草药对供试耐药株均有较强的抑制活性，其中黄连、大黄和金银花的抑菌活性尤为明显，其MIC值分别介于1．96～125g／L、7．84～125g／L和15．68～250g／L。5个复方配伍中以复方5的配伍效果最好，其MIC值为1．96～15．68g／L，抑菌活性显著优于单味药；其次是复方1和复方3，其MIC值为1．96～62．72吕／L；复方2和复方4的配伍效果差，其MIC值为31．36～125g／L。结论4种23株常见病原菌均为耐药菌株，产生ESBLs是铜绿假单胞菌高度多重耐药的主要机制之一。黄连、大黄、金银花和复方5配伍对常见病原菌耐药株具有良好的抑菌活性。

Objective To elucidate the present drug resistant situation and resistant mechanism of common pathogens isolated from aquatic animals in Anhui, to detect bacteriostasis activity of 27 kinds of Chinese herb and 5 compounded extracts on drug resistant strains in vitro. Methods K-B disc agar diffusion method and double-disk synergy method were used to detect the drug resistance and ESBLs of common pathogens respectively, bacteriostasis activity of Chinese herb medicine were assayed by Plat stiletto method and improved microdilution method in vitro. Results 23 strains of four kinds of common pathogens had resistance to common antibiotics at different extent. 2 Psendomonas neruginosa strains had the broadest spectrum of drug resistance and their resistant rate to 14 kinds of antibiotics were 100%. Only 2 Psendomonas neruginosa strains in all detected pathogens might produce ESBLs and the rate of ESBLs was 8.69%. Rhizoma coptidis, Rheum officinale, Flos lonicerne ,Spica prunellae, Euphorbia humifusa, Cortex Moutan, Portulaca oleracea L. and Fructus forsythiae had strong inhibition activity to detected pathogens, especially Rhizoma coptidis ,Rheum officinale, Flos lonicerae, and their MIC were among 1.96～ 125 g/L,7.84 ～ 125 g/L, 15.68 ～250 g/L respectively. The fifth compounded extract had the best compatible effect and its MIC was 1.96 ～ 15.68 g/L and its bacteriostasis activity was significantly higher than single-flavor Chinese herb; followed by the compounded extract 1 and 3, their MIC were from 1.96 to 62.72 g/L; compounded extract 2 and 4 had poor compatible effects, MIC were 31.36 ～ 125 g/L. Conclusions 23 strains of four kinds of common pathogens were all drug resistant strains, producing ESBLs was one of the major multi-drug resistant mechanisms of Psendomonas neruginosa. Rhizoma coptidis, Rheum officinale, Flos lonicerne and compounded extract 5 had good bacteriostasis activity on drug resistant strains of common pathogens.