Identification And Resistance Of Swine Pathogenic Salmonella In Shandong Province

Recent years, the infection diseases of swine was becoming more and more serious. However, some diseases caused by bacteria, especial Salmonella, are more prevalent and have caused numerous losses in swine industry. Most strains of Salmonella are more and more widespread. The spectrum of the resistence becomes wider and wider. Some strains even could resist the new antibiotics which have not been used in animal. Bacteria with drug-resistant plasmid could be transferred from animal to human, so the abuse of large dosage of antibiotics not only makes it difficult to cure the disease, but also makes it latent harm to humankind. In this paper, we report the isolation, purification, identification, invH gene amplification and pathogenicity of Salmonella in swine. The interrelation between drug-resistance and aminoglycosides-resistance gene was investigated. In order to show the inspection and drug-resistance of Samolella in Shandong province and provide the therotical basis for controlling Salmonlella. The study includes three parts:PartⅠ: Separation and identification of pathogenica swine Salmonella and invasion gene of invH201 samples were collected from seven large hogpen in different parts of Shandong province and gained 135 bacteria. All were identified by culture, staining, biochemical test and ATB biochemical-system. 95 strains were identified Salmolella in the end; The invH gene of 95 strains were amplified. The result was that 87 strains were identified. The positive compatible rate was 91.6%(87/95).In the end, Choosing 25 Salmonella which were identified by biochemical test and invH gene PCR to test the pathogen of separated Salmonella. The result was that the strains which include WJS3-2, WWS3-1, JZS42, JZS18,JZS7, JYS133, LJS5, WJS1-1, WJS2-3,LJS16,PLS24-3,PLS7-1,PLS27-1 were pathogenic to white mouse. The death rate was over 80%. At the same time, There were Only two strains of no-pathogen to the white mouse. The payhogenic rate was 92.0% (23/25). The result was matched with the invasion characteristic of invH gene.Part II: Inspection of Antibiotic Resistance of pathogenic Salmonella from SwineWith 27 kinds of drug sensitivity slips of clinical frequently used antibiotic by kirby-Bauer mean to test the drug sensitivity for the isolated 95 strains, we found that the sensitivity drug of the Salmonella isolated from different hogpen was resembled to the drug, and the sensitivity drug of the Salmoella isolated from the same hoghen was the same, too. At the same time, the separated strains of different parts were some difference. Results showed that isolated strains resist 28 types of drugs. The high drug-resistance of all strains was Proctaphlin, Trimethoprin, Sulbactam, Rifampicin, Florfenicol, Clindamycin, Penicilin G, Terramycin. The multi-resistance was over ten-resistance. The percentage of the resistance was 69.5% in the 95 strains. The hightest distances of drug-resistance rate were the north 2 and west-south 2 of Shandong province. The condition were matched with the drugs were abused in the two parts.Part III: Study on the molecular epidemiology of aph(3′)-IIa gene of pathogenic Salmonella19 strains were choosen from the isolated sample, at the same time, the19 strains were positive by biochemical test, the identificatione by invH gene test and Aminoglycosides-resistance test. The 19 strains were used to test aph(3′)-IIa gene. The result was that 14 positive strains were identificated from the tested strains. Compared to the results of the drug-susceptibility tests, the method of PCR showed 73.7% concordance on positive rate. Detected aph(3′)-IIa gene of 3 strain which were from the 13 positive strains had the same gene sequences as the genes (AF078924.1,AF188331.1,AY333434.1,AY598820.1,DQ842000.1) published in GenBank. The result was that the isogeny rate was 100%.