Isolation And Identification Of Chlamydia Psittaci From Broiler With Chlamydiosis

Serum samples from seven flocks of suspected broilers with Chlamydiosis were screened in Beijing suburb areas. Based on the positive results of serological test - indirective hemoagglutinate inhibit test (IHI), The pathogen was isolated from lung of broilers by inoculating SPF embryo eggs and McCoy cells, then, it was identified to be Chlamydia psittaci by the following experiments, such as dyed by Gimenze, iodine and immunofluorescence assay. In order to evaluate the activity of isolated pathogen, the test of inhibitor of sulfantrimum sodium was performed.Two different sets of oligonucleotide primer were simultaneously used to amplify 627bp gene fragment and 111bp gene fragmen. These two primers were designed according to the sequences of the rrn operon sequence of Chlamydia psittaci, that is, 16S ribosomal DNA sequence and 16S-23S ribosomal DNA spacer sequences. This duplex PCR assay was able to detect as little as 500fg/μl. Among 100 clinical samples, the average positive rate of duplex PCR was 83.4-97.2 percent and the coincident rate of duplex PCR was 95 percent, both of which were higher than that of the immune fluorescence method, 71.3-80.7 percent, 80 percent, respectively.This result showed further that pathogen we have isolated was Chlamydia psittaci. Moreover, compared with the pathology of broilers infected both naturally and experimentally with Chlamydia psittaci, it was demonstrated for the first time that broiler was natural as well as experimental host of Chlamydia psittaci.On the basis of serological investigation and pathogenic isolation, the broilers were inoculated with recombinant Major Outer-Membrane Protein (r-MOMP) vaccine of Chlamydia psittaci (Cps) through cervix hypodermic. Immunization with r-MOMP can generate humeral and cellular immune responses in broiler. It was no doubt that new approach was offered to prevent broiler free from chlamydiosis.