Research On The Haemophilus Parasuis Mixed-infection With CSFV And PRV And Its Plasmid-mediated ?-lactamase Resistance Genes In Sichuan Province

Haemophilus parasuis is symbiotic bacteria in upper respiratory tract of pigs, however, it will invade body and cause systemic diseases when under the certain condition. At present, this disease has become one of serious influence pig-breeding industry development infectious diseases. In this study, we detected the mixed-infection of H. parasuis, CSFV and PRV in Sichuan Province. Meanwhile, we tested the ?-lactam antibiotics resistance of H. parasuis in Sichuan and investigated its plasmid-mediated ?-lactamase resistance genes. These experiments provided a scientific reference for preventing this disease in Sichuan. The main results are as follows:1. The investigation of the mixed-infection of H. parasuis with CSFV and PRV in Sichuan Province75 clinical samples of illness pigs which were isolated HPS and suspected pathology damage with CSFV and PRV were collected from 18 different districts of Sichuan Province. The DNA and RNA which were extracted from 75 clinical samples were detected by RT-PCR and PCR respectively. The results showed that:the mixed-infection rate of H. parasuis and CSFV in Sichuan Province was 37.3%(28/75), and mixed-infection rate of H. parasuis and PRV was 16.0%(12/75), besides, the mixed-infection rate of H. parasuis and CSFV?PRV was 9.3%(7/75). The above results indicated that the mixed-infection in Sichuan was seriously.2. The detection result of plasmid-mediated ?-lactamase resistance genes investigation of H. parasuis isolates from Sichuan Province5 kinds of ?-lactam antibiotics resistances and plasmid-mediated ?-lactamase resistance genes of 97 isolated H. parasuis from Sichuan Province were detected by Kirby-Bauer method and PCR respectively. The results indicated that 86.6%(84/97) of isolates were resistance. The resistant rates to ampicillin, amoxicillin, penicillin, cefotaxime, cefazolin were 63.9%(62/97),56.7%(55/97),74.2%(72/97), 37.1%(36/97),29.9%(29/97), and the situation of multiple drug resistance was very serious. The plasmids of 86.6% isolates carried one P-lactamase resistant gene at least. The rates of genes detection were:TEM-57.7%(56/97), SHV-33.0%(32/97), CTX-17.5%(17/97), OXA-19.6%(19/97), DHA-2.1%(2/97), and a total of 32 isolates carried 2-3 kinds of resistant genes. The coincidence rate of resistant genotype and phenotype was 88.1%(74/84). Results showed that the p-lactam antibiotics resistances of H. parasuis Sichuan isolates was serious and the carrying rates of its plasmid-mediated P-lactamase resistance genes were high. In addition, the high coincidence rate of resistant genotype and phenotype indicated that preliminarily determined resistant strains by detecting drug-resistant genes is feasible.