Plasmid Diversity and Antibiotic Resistance of Avian Pasteruella multocida

This study aimed to determine the drug-resistance and plasmid-carrying properties of the 20 strains of Pasteurella multocida isolated from avian sources.Their sensitivity to antibiotics was determined by using the diffusion test on paper,and the plasmids extraction by means of the alkaline lysis method.More than 80% of the isolated strains were found sensitive to Ofloxacin,Rifampin,Cefazolin,Polymysin B,Doxycycline,Levofloxacin,Ampicillin,Enrofloxacin and/or compound sulfamethoxazole.The plasmid-carrying rate of the isolates was 65%with 1to 7plasmids found in them.There was no correlation between the drug resistance and plasmid-carrying of the bacteria,as the strains that carried plasmids were shown only resistant to Florfenicol,Polymysin B and compound sulfamethoxazole.It suggested, however,that Ofloxacin, Rifampin, Cefazolin, Polymysin B,Doxycycline,Levofloxacin,Ampicillin,Enrofloxacin and/or compound sulfamethoxazole should be preferential for treating the avian cholera.And,the plasmids found in the P.multocida isolates might be associated with the bacterial resistance to Florfenicol,Polymysin B and compound sulfamethoxazole.