Isolation,identification,and drug resistance analysis of a Riemerella anatipestifer Liaoning strain from chickens
Feng Shuo
Zhou Tiezhong
Li Bing
Dong Xiaoping
Wang Rongqian
Liu Haiyu
Wang Yongming
Liu Yingzi
Abstract：To clarify the biological characteristics,including pathogenicity and drug resistance,of a Riemerella anatipestifer(RA)Liaoning strain isolated from chickens,tissue samples such as liver and joints were aseptically collected from dead chickens for isolation and culture.The isolate was identified using bacteriological and molecular biological tests.Serotyping was performed via agglutination tests,pathogenicity was evaluated by intraperitoneal injection in chicks,and drug sensitivity was tested using the K-B method.The results showed that the colony morphology,staining characteristics,and biochemical reactions of the cultured bacteria were consistent with RA characteristics.PCR identification targeting RA-specific genes yielded an amplification product of approximately 626 bp,matching the expected band size.Sequencing analysis revealed that this gene sequence had the highest homology(99.86%)with the published RA standard strain(NR026025.1)in GenBank.Serotyping by agglutination test identified the isolate as serotype 1.Animal pathogenicity tests confirmed the isolate's strong pathogenicity,with incidence rates reaching 100%in both mice and chicks,and mortality rates of 30%and 60%,respectively.The isolate was sensitive to seven drugs,including ceftiofur,doxycycline,and florfenicol,but resistant to gentamicin,kanamycin,azithromycin,streptomycin,and polymyxin B,indicating it is a multidrug-resistant strain.The study demonstrates that the chicken-origin RA Liaoning strain(JMAV23.202501)is serotype 1 and exhibits strong pathogenicity in both mice and chickens.
Keywords：ChickenRiemerella anatipestiferIsolation and identificationPathogenicityDrug resistanceLiaoning strain
Publication Date：2025-12-15
Online Publishing Date：2026-01-12(First online date of this platform, not the publication date of the document)
Pages：7( 16-22 )