Isolation and identification of pathogenic Enterococcus faecalis from chicks and the analysis of its drug resistance

Abstract:

[Background] As a normal intestinal flora of human and animal, Enterococcus faecalis was also a conditional pathogenic bacterium, which could infect human and animal. [Objective] To analyze the pathogen of which cause the death of the chicks in chicken farm, and choose the effective drug. [Methods] The pathogen was isolated from clinical sample based on the clinical symptoms and pathological examination. Then, the physiological and biochemical characteristics, 16S rRNA gene sequence, pathogenicity and drug resistance were conducted to identify the pathogen. Drug therapy was performed to screen the effective drug towards the pathogen. [Results] The clinical symptoms of lethargy, paralysis and ataxia in sick chick could be observed. Swelling spleen, yellow, swelling, brittle and fragile liver with a small amount of bleeding points, thickened and bleeding intestinal mucosa, and mild cerebral edema could be observed by pathological examination. A gram-positive coccus, named CJ517 after purification and culture, was isolated from liver tissue. It was identified as Enterococcus faecalis according to physiological and biochemical characteristics and 16S rRNA gene sequence analysis. The pathogenicity test showed that the mortality rate of CJ517 on mice was 66.67%. It is sensitive to cefotaxime, fosfomycin, butyramecana, while as resistant to doxycycline, kanamycin, neomycin and florfenicol. The disease was relieved after treating with sensitive drug combined immunopotentiator. [Conclusion] The result could provide reference for diagnosis and treatment of disease caused by the infection of Enterococcus faecalis.