Surveillance And Analysis On The Antibiotic Resistance Of Riemerella Anatipestifer

The resistance to 23 antimicrobial in 102 isolates of Riemerlla Antipestifer were detected by K-B method and broth microdilution method .The result indicated that 88 isolates showed a greater or lesser degree resistance to deffrent antimicrobial: the isolates has a higher resistance to aminoglycoside, quinolones and sulfa .Some isolates showed resistance to multiple antibiotics and displayed a highest level resistance to pipemidic acid and nalidixic with a frequency of 73.5% and 81.4% respectively. There are three isolates resistance to seven in 23 antibiotics in K-B method and two isolates resistance to 5 in 8 antibitics in broth microdilution method.In order to detected the resistance gene and found the mutation of Riemerlla Antipestifer .this study developed the method based TenneyJH, MeackRW, et al.and induced some isolates' resistance to Amikacin, ciprofloxacin and norfloxacin sucefully.PCR was used for the amplification of Intergron gene of all the resistant isolates.There is a Intregron was detected with a size of 1586bp,which contained aadA2 gene and dhfrl gene assolated with the resistance.Authed amplified the gyrA gene firstly in the world,include quinolone resistance-determining region(QRDR),and analyzed the amino acid of resistance to quinolones and susceptibility to quinolones. Riemerlla Antipestifer and Enterococcus faecalis are compared, based on the E. coli co-ordinates, the hotspots most favoured giving rise to decreased susceptibility to quinolones are at serine 83 and aspartate 87,which exactly located the same mutation of the QRDR from very different bacteria ranging from E. coli to Pseudomonas aeruginosa, Mycobacterium tuberculosis .The aminoglycoside-modifying enzymes (AMES) were detected by PCR and the ant(3")-â…  gene was found in a isolate.which indicated the AMES has occur in Riemerlla Antipestifer in China.