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Extensive use of antibiotics in aquaculture increased bacterial resistance to antibiotics and resistant pathogens may be transmitted through the food chain to humans, so that the body becomes resistant gene repository, serious harm to human health. Aquaculture and environmental issue of bacterial resistance has caused widespread concern around the world. In this thesis the incidence and level of resistance of Salmonella in Foshan, Guangdong Province, South China Sea fish pond ecosystem, to detect Salmonella carrying different resistance genes. Up the fish pond ecosystem grass carp, duck, fish living area of ??land, water and ducks living area soil and water samples were collected by biochemical identification and identified by PCR were detected Salmonella 34 (guts six, six fish ponds soil, fish five ponds, Duck, 6, 6 duck farm soil, the duck farm water 5), fish ponds, water and duck farms water Salmonella detection rate of 7.1%, the rest are 8.6%. Bacterial community diversity and specificity of PCR-DGGE (denaturing polyacrylamide gel electrophoresis) technical analysis of the microbial community structure of the farming system, display the intestines of animals and the environment, each has different the bit microecological abundance and advantages of flora . Kirby-Bauer method on 17 kinds of antibiotics in vitro sensitivity tests, including ampicillin, streptomycin, neomycin, ceftazidime, cefotaxime, nalidixic acid, trimethoprim, sulfamethoxazole, cotrimoxazole , chloramphenicol, tetracycline, furan phenytoin, erythromycin, penicillin, polymyxin B, tigecycline and florfenicol test. Susceptibility results from the pond ecosystem separation Salmonella drug resistance is widespread, all strains showed weight and heavy multi-drug resistant, 97% of the drug combination of performance ampicillin / neomycin The hormone / erythromycin / penicillin jointly resistance to cephalosporins, nitrofurantoin and polymyxin B resistance rates were sensitive to tigecycline. The this study multiplex PCR reaction system to detect Salmonella 22 resistance gene include the aadA, AAC (3) -1, aphA1, aac (3)-IV, ereA.MOX, DHA, EBC, FOX, CIT, blaSHV blaOXA, blaTEM, tetA, tetB, tetC, sull, dhfrI, dhfrV, catI, cmlA and Flor. Using the seven duplex PCR reaction system detection of drug resistance genes SULI, blaSHV, CATI, dhfrV, Flor, aadA and blaOXA, two six-plex PCR reaction system were detected resistance genes of blaTEM, of CMLA, CIT, Erea, dhfrI, AAC (3) - I and resistance gene aphA1, MOX, DHA, EBC, aac (3)-IV, Fox, triple PCR reaction system to detect tetracycline resistance gene (TETA tetB the tetC). The results showed that 34 strains of Salmonella from different farming systems was detected in 17 drug-resistant gene (Erea the FOX, blaSHV, CATI and tetC genes not detected), aminoglycoside resistance gene detection rate aadA GT; aphA1 the GT; AAC (3)-IV gt; aac (3)-I; ampicillin-resistant gene detection rate of CIT gt; the DHA gt; EBC; the blaOXA gt; beta-lactam resistance gene detection rate of blaTEM; tetracycline class resistance gene detection rate Teta gt; tetB which not detected tetC; the sulfa-resistant gene sulI in detection rate of 32.4%; the the trimethoprim the class dhfrV and dhfrI detection rates were 11.8% and 5.9 %; chloramphenicol gene detection rate the CMLA gt; Flor 17.6% and 8.8%, respectively. Phenotype and genotype results of the sensitivity test comparison: the most positive coincidence rate is higher than 40%, of which aminoglycoside positive coincidence rate up to 52.9%, multiplex PCR reaction system with fast Province, specificity and high . The study also triplex PCR reaction system detected 34 resistant Salmonella carrying the integron (intI1, 2, 3) the situation and further amplification primers to conserved sequences integron-positive strains of class 1 integron sub (intI1) can hypervariable region. The results showed integrons are widely distributed in the various strains, 91.2% of the strains can detect the presence of integrated sub-30 containing a class 1 integron, a simultaneous detection of Class 1 and Class 2 integrons were not detected 3 integron. There are two types of 1600bp and 160bp resistant salmonella in the pond ecosystem class 1 integrons are prevalent in more than one gene cassettes and Ini1 variable region amplified fragment size. This study reveals the existence of multi-drug resistant Salmonella in the pond ecosystem, and drug-resistant strains generally contain resistance genes and the integrase gene, integrated child can carry the horizontal transfer of multiple drug resistance genes in breeding ecosystem, leading to resistance The medicinal properties of diffusion and spread of the food chain and pose a security risk to human health.
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