ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2014, Vol. 45 ›› Issue (11): 1858-1865.doi: 10.11843/j.issn.0366-6964.2014.11.017

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Isolation，Identification and Diversity Study of Escherichia coli from Broilers Infected with Immunosuppressive Viruses

JU Si-di1，DONG Xuan1，ZHAO Peng1，LI Yang1，MENG Fan-feng1，SUN Peng1，DONG Xiang-lei2，GAO Song2，CUI Zhi-zhong1*   

  1. (1.College of Animal Science and Technology，Shandong Agricultural University，Taian 271018，China；2.College of Veterinary Medicine，Yangzhou University，Yangzhou 225009，China)
  • Received:2014-04-08 Online:2014-11-23 Published:2014-11-23

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Abstract:

This study aimed to investigate the diversity of serotype and drug resistance of E.coli from the secondary infection of broilers that primarily infected by immunosuppressive viruses.E.coli isolates derived from one-day-old broilers single-infected or co-infected with avian leukosis virus subgroup J (ALV-J) and reticuloendotheliosis virus (REV) were isolated，identified and used for drugs sensitivity experiment.Five red or (and) white clones were picked from the diseased organs.Results showed that 516 E.coli isolates were isolated from 58 diseased chickens and identified from two repeated experiments including 445 red colonies and 71 white colonies.Results also reveal that the co-infection could infect more serious mortality and among these 516 tested E.coli colonies，12 serotypes of O-antigen were identified.E.coli of different serotypes was even isolated from the same organ in the same bird.Then 17 groups of colonies (5 same O-serotype colonies isolated from the same organ in the same bird were identified as a group of colonies) were selected to drug susceptibility test for 12 kinds of common antibiotics.The results showed that the minimum inhibitory concentration was from 0.05 to 51.20 mg•mL－1 in the third group to colimycin and from 0.05 to 51.20 mg•mL－1 in the seventeen group to amikacin.However，differences in the other groups were not significant.The high-degree diversity of E.coil isolated from our experiments proved that the infection was the secondary E.coil infection.It was happened in the immunosupression condition under the viruses infection.At the same time，the diversity of drug resistance is the genetic basis for resistant strains rapidly generated from the E.coil in vivo under the condition of irrational use of antibiotics.

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