China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (4): 1695-1706.doi: 10.16431/j.cnki.1671-7236.2023.04.040

• Basic Veterinary Medicine • Previous Articles     Next Articles

Isolation,Identification,Virulence and Drug Resistance of Salmonella from Yellow Chicken

WU Zhi1, ZHANG Cong1,2,3, YUAN Huisha1,3, DONG Hongyan1, DAI Lixia3, JIA Luqi4, WU Shuang1, ZHU Shanyuan1   

  1. 1. Jiangsu Agri-Animal Husbandry Vocational College, Taizhou 225300, China;
    2. Yangzhou University, Yangzhou 225000, China;
    3. Hesheng Food Group Co., Ltd., Taizhou 225300, China;
    4. Shandong Baisheng Pharmaceutical Co., Ltd., Taian 271000, China
  • Published:2023-04-06

Abstract: 【Objective】 The purpose of this study was to investigate the prevalence virulence and drug resistance of salmonella strains isolated from Yellow chicken in a large-scale hatchery.【Method】 The yolk swabs of weak chicks were collected and inoculated with selective medium for purifying and isolating bacteria.The isolated strains were identificated by Gram staining,microscopic examination and PCR amplification were carried out according to the Salmonella specific gene invA.Kirby-Bauer disk diffusion method was used for drug sensitivity test and amplify drug resistance genes to investigate and analyze the bacterial resistance of clinical isolates.The pathogenicity of the isolates was tested by SPF Kunming mice and the related virulence genes were amplified by PCR. 【Result】 The results showed that five isolated strains (JSS-Q3, JSS-Q4, JSS-Q5, JSS-Q8 and ZJS-C1-11) were suspected to be Salmonella.Colorless transparent colonies were formed in Eosin-Methylene blue medium,and purple transparent colonies were formed in Salmonella chromogenic medium,which were detected as short rod-shaped Gram-negative bacteria.Salmonella specific gene (invA) was positive and 99% similarity with Salmonella and the specific gene (IpaJ) amplification of Salmonella Gallinarum was positive,so the five isolated strains were all Salmonella Gallinarum.The results of virulence gene amplification showed that a total of fifteen virulence genes were detected,of which eleven were 100%.Drug resistance analysis showed that five isolated strains had strong resistance and were only sensitive to some antimicrobial agents.The isolates were sensitive to cefepime,flufenicol and enrofloxacin.In addition,JSS-Q5 and JSS-Q8 were sensitive to polymyxins B and neomycin,respectively,JSS-Q3 was sensitive to ceftazme and macromycin,and ZJS-C1-11 was sensitive to cefaclor,macromycin and polymyxins B.Some strains carried blaSHV,blaTEM,tet(A),tet(B) and other drug-resistant genes.Pathogenicity analysis showed that JSS-Q8 and ZJS-C1-11 strains were highly virulent and lethal to mice.【Conclusion】 The Salmonella isolates from Yellow chicken hatchery involved in this study were Salmonella Gallinarum.All of them showed multiple drug resistance and some of them were highly pathogenic,which might be one of the important reasons affecting the hatchery hatching rate and weak chick rate.The results of this study provided certain experimental basis for the detection,diagnosis and treatment of salmonella.

Key words: Salmonella; chicken; multiple drug resistance; virulence gene; resistance gene

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