水产致病菌耐药基因的研究

采用纸片扩散法(Kirby-Bauer法)研究不同来源的54株水产细菌对10种抗生素的敏感性,筛选获得耐药菌株并研究其耐药基因。根据GenBank中注册的耐药基因序列,针对不同抗生素的耐药基因设计相应的引物,对耐药基因进行扩增,检测耐药菌株中耐药基因的分布。结果由54个受试菌株中检测出42个耐药株,耐药率为77.8%。其中37株对3种以上抗生素产生耐药,多重耐药率为68.5%。以耐药菌株质粒为模板,扩增磺胺类耐药基因sul2、氯霉素耐药基因cat1、cat2、cat3、cat4、卡那霉素耐药基因aadB、喹诺酮耐药基因gyrA,结果显示:sul2基因阳性9株,3株氯霉素cat2阳性,4株氯霉素cat3阳性,1株氯霉素cat4阳性,3株aadB阳性。质粒上耐药基因的检出率分别为50%、27%、36%、9%、60%。

Antibiotic resistant genes in aquacultural bacteria

54 aquacultural bacterial strains originated from different area were tested for the drug sensitivity of 10 common antibiotics determined by Kirby-Bauer disk diffusion according to NCCLS.With specific primers designe according to the reported sequences in GenBank,polymerase chain reaction(PCR) assay were used to amplify the antibiotic resistant genes and study the mechanisms of drug resistance.42 of 54 gram-negative bacteria were identified as resistant bacteria(77.8%),and 37 strains(68.5%) had the multi-resistances for resistance to more than 3 antibiotics.The resistant genes on plasmids were detected by PCR method.9 strains were tested including trimethoprim-sulfamethoxazole resistance gene sul2,3 strains possessed chloramphenicol resistant gene cat2,4 strains have chloramphenicol resistant gene cat3,only 1 strain was amplified to have chloramphenicol resistant gene cat4,and 3 strains were detected with kanamycin resistant gene aadB.The detection ratios of the resistant genes in plasmid were 50%,27%,36%,9%,60%,respectively.