Establishment Of Detection Methods Of Resistant Genes For Swine Salmonella And The Application

Salmonella is one of the most important pathogens, which has a wide range of animal hosts. Salmonella infections appear to be one of the most typical examples of an enteric disease implicated mainly in common-source epidemics. The animal-originated Salmonella is the major pathogens to human foodborne illness in the world. The resistance of Salmonella emerged due to the wrong use of the antibiotics and the feedstuff additive at the clinic. The antimicrobial resistance in Salmonella has been a cause for concern in clinic. Once the bacteria have the resistance, the original effective drugs become no effect. Consequently, the illness will be worsen and even the life will be endangered.The bacteria have many kinds of resistant mechanisms and the transmission speed is very fast. The resistance can transmit to human by the food chain, which impacts badly on the development of stockbreeding and human health. So it is very important to prevent and control the emergence and transmission of resistance to antibiotics. In order to detect the resistance as soon as possible, the molecule detection to resistant genes is a kind of easy, rapid and efficient method without doubt. In this research, we carried out the following works including Salmonella identification, drug resistance test and drug resistance gene detection for Salmonella isolates:1. We isolated 41 Salmonella from the clinical cases.2. We researched the drug resistant situation of swine pathogenic Salmonella from the clinic by carrying on the drug susceptible test for all the isolates.3. Refering to the resistant gene sequences in GenBank, we designed 48 pairs of PCR primers and amplified all the resistant genes responsible for 5 catogories of antimicrobial drugs by PCR including 11 kinds of genes such as OXA-1, aadA1, aadA2, aadB, aph(3')-II, aacC2, cat1, tet(B), dhfrXII, dhfrXIII, dhfrVII.4. We established the PCR methods for detection of resistance genes for four antimicrobial drugs and there is in high agreement with the drug resistance test. The resistant genes included: tetB, cat1, aadA2, aacC2, dhfrXII, dhfrXIII and these methods paved a way tostudy the resistant situation at the molecular level.