In order to explore the causes of diseases with listlessness and diarrhea as the main symptoms in a large-scale rabbit farm in Henan Province,six dead rabbits were randomly selected for autopsies,and their tissues were observed for pathological changes.After purification,separation and enrichment by four-zone marking method,they were cultured in ordinary agar medium,blood agar medium and MacConkey agar medium respectively,and the suspected pathogenswere identified by PCR,coccidia detection,biochemical identification,PCR amplification,sequencing and sequence analysis of 16S rRNA gene.The autopsy results showed that the kidneys of the dead rabbits were khaki,the liver was swollen with bleeding spots,the thymus was bleeding,the spleen was atrophied in dark brown,and the lungs were white with scattered hemorrhagic spots.The identification results of suspected pathogenic bacteria showed that Escherichia coli,Klebsiella pneumoniae,Clostridium welchii,Salmonella,Bordetella and coccidium were all negative.Moreover,through bacterial isolation and culture,PCR amplification and sequencing of 16S rRNA gene and the construction of phylogenetic tree,the pathogen causing the death in the rabbit farm was further determined as Proteus mirabilis,and named it HN001 strain.The virulence gene of Proteus mirabilis was detected by PCR,and pathological tissues such as liver,kidney and intestine of diseased rabbits were collected to make pathological sections to observe its pathological changes.Rabbits were infected with HN001 strain at 1011cfu/mL,and were killed one week later.The pathological changes of rabbits in each group were observed,and the pathogenic bacteria were isolated and identified again from the internal organs of rabbits.The PCR results of virulence genes showed that the flagella gene FliL and fimbriae structural subunit gene MrpA were positive in HN001 strain,while the hemolysin gene HpmA,metalloprotease structural subunit gene ZapA and the regulatory gene RsbA of fimbriae migration ability were negative.The histopathological results showed that the kidney,liver,thymus,spleen,lung and jejunum were seriously damaged,and the main pathological changes were inflammatory cell infiltration and scattered red blood cells.The results of pathogenicity test in rabbits showed that the symptoms of this pathogen were similar to those of naturally infected rabbits and the symptoms of organ autopsy,but the lesion degree was less severe than that of naturally infected rabbits.The same strain as the infected bacteria was isolated from the diseased rabbit again,which indicated that Proteus mirabilis was the pathogen of the outbreak of the disease in this rabbit farm.This study provides reference for the prevention and control of rabbit Proteus mirabilis disease.
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NSTL
维普
万方数据
