China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (2): 435-442.doi: 10.16431/j.cnki.1671-7236.2022.02.004

• Biotechnology • Previous Articles     Next Articles

Isolation, Identification, 16S rRNA Gene Sequencing and Genetic Evolution Analysis of Aeromonas aeruginosa from Duck

QIAO Hongxing1,2, DING Yong3, ZHANG Liheng1,2, SONG Yuzhen1,2, DONG Qing1,2, BIAN Chuanzhou1,2, ZHAO Junqiang4   

  1. 1. College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, China;
    2. Henan Province International Joint Laboratory of Animal Intestinal Diseases in Henan Province, Zhengzhou 450046, China;
    3. College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China;
    4. Henan Rongruixiang Pharmaceutical Co., Ltd., Shangqiu 476200, China
  • Received:2021-07-02 Online:2022-02-05 Published:2022-01-27

Abstract: 【Objective】 The experiment was aimed to study the pathogenic bacteria of acute death of ducklings in a duck farm in Henan province and its phylogenetic status.【Method】 The liver and spleen of dead ducks in the diseased duck farm were collected.The bacterial morphology, Gram-staining, biochemical characteristics, sequence analysis of 16S rRNA gene, drug sensitivity test and pathogenicity test were carried out.【Results】 The isolated bacteria grew on blood agar medium with smooth, convex, milky white and α-hemolytic Gram-positive cocci.Biochemical test results showed that the isolated bacteria were positive for maltose, sucrose, raffinose, nitrate reduction reaction, MP-VP test, urea, lysine decarboxylase, ornithine decarboxylase and aescin, and negative for xylose, lactose, glucose, sorbitol, hydrogen sulfide, citrate, peptone, mannitol, phenylalanine and methyl red.The results of 16S rRNA gene sequencing and BLAST comparison results showed that the 16S rRNA gene sequence of the isolated strain was 94.8%-99.9% similar to that of Aerococcus viridans published on NCBI, and the similarity with strains Mnlv1, Mnlv2 and W66 was the highest, up to 99.9%.The similarity with strain GXBl-1 was the lowest, which was 94.8%.Phylogenetic tree analysis showed that the isolated bacteria belonged to the same genus and group on the same branch as strains of Aerococcus viridans FL09, 15MS and Mnlv2 etc., and had the closest genetic relationship with FL09.The results of drug sensitivity showed that the isolated strain was sensitive to fosfomycin, ampicillin and amoxicillin, moderately sensitive to penicillin, neomycin and amikacin, it was resistant to rifampicin, neomycin, bacitracin, erythromycin and enrofloxacin.The results of pathogenicity test showed that the strain was lethal and increased with the increase of inoculation concentration.【Conclusion】 This study determined that the pathogen causing the acute death of ducklings in a duck farm in Henan province was Aerococcus viridans, which provided a reference basis for clinical diagnosis and treatment of the diseases caused by this bacteria.

Key words: duck; Aerococcus viridans; isolation and identification; 16S rRNA; genetic evolution

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