• Korean Journal of Veterinary Service
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• v.22 no.3
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• pp.257-262
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• 1999

Riemerella anatipestifer (RA) infection is a contagious disease of domestic ducks, turkey, and various other birds. In a flock of mallard ducklings, about 30% of the birds, 3 weeks old, showed lethergy, greenish diarrhea, tremor of head and neck, and died 2-3 days after signs appeared. Grossly, fibrinous exudates covered the heart and surface of the live. Microscopically, mononuclear cells and heterophils were primarily inflammatory cells in the exudate. These were also observed in the meninges in brain. Microbiologically, gram (-) short rod bipolar shaped bacteria were recovered on blood agar and agglutinated by antisera of R anatipestifer. Sulfamethoxasole/trimethoprim were administered and clinically effective. This case was a R anatipestifer infection caused fibrinous pericarditis, hepatitis and meningitis in mallards.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.339-345
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• 2008

This survey was carried out to investigate the infection rate of Riemerella anatipestifer from domestic ducks by isolation. A total of 145 samples (nasal swabs and carcasses) were collected from farms to examine the biochemical properties and antimicrobial susceptibility test from November 2006 to February 2008. Riemerella anatipestifer was isolated from 13 of 145 sample and isolation rate was higher in the ducks below 25 days (76%, 10/13 isolates) than those over 26 days (23%, 3/13). However, there was no significant difference in isolation rate between region. The biochemical properties of isolate were Gram negative (-), non-fermentative rod that grows fastidiously on routine media. In the test of antimicrobial drug susceptibility the isolates were susceptible to tetracycline(100%), enrofloxacin (77%), ampicillin (70%).

• Korean Journal of Veterinary Service
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• v.31 no.1
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• pp.37-42
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• 2008

Riemerellosis, contagious disease of domestic ducks in Korea, occurred in December of 2007 in a farm located in Eumsung, Chungbuk province. The affected ducks were 22 days old and the owner reported that almost one hundred of ducks had died everyday for a few days after infection. Clinical signs were listlessness, ocular and nasal discharge, greenish diarrhea, ataxia, tremor of head and legs, and coma. On necropsy we found fibrinous exudate, which involved serosal surfaces in general, but most evidences were in the pericardial cavity and over the surface of the liver. The causative agent was isolated from the liver of the affected ducks and identified as Riemerella anatipestifer using biochemical tests. Also, the isolate was susceptible to ampicillin, cephalothin, sulfamethazole/trimethoprim, Florfenicol among the 23 species antibiotics (AST Discs, OXOID) used in our laboratory. Further studies should be needed for the more effective control and better epidemiological information such as pathogenicity, serotype, genotype and treatment.

• Proceedings of the Korean Society of Veterinary Service Conference
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• 1999.05a
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• pp.173.2-174
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• 1999

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.327-335
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• 2021

Riemerella anatipestifer (RA) can cause septicemia, polyserositis, and ataxia in ducks. It can also colonize the upper respiratory tract of healthy ducks. These differences in pathogenicity are probably the result of diverse mechanisms of virulence in different strains. Since serum resistance is a feature frequently found in systemic pathogens, 130 RA strains having different clinical origins were tested. A variety of serum susceptibility levels were detected. Pharynx strains from healthy ducks were mainly susceptible to the bactericidal effect of the serum, while systemic strains were serum resistant. Heat-treatment of the sera abolished the bactericidal activity, indicating that complement is a key factor in this effect. In an attempt to associate serum-resistance to surface determinant genes of the bacteria, we screened for six genes involved in lipopolysaccharide synthesis and membrane proteins in RA. Of these, three genes (AS87_09335, AS87_00480, and AS87_05195) encoding outer membrane proteins might be implicated in serum resistance statistically. The results indicate that serum resistance is a virulence mechanism in RA.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.97.1-97
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• 2003

An antagonistic bacterium, KJ1R5,, to Phytophthora capsici was obtained from root interior of a healthy pepper plant. To identify the bacterial antagonist, 16S rDNA sequence analysis, Biolog system, fatty acid methyl-esters (FAMEs), and physiological and biochemical characterization were conducted. The determined 165 rDNA sequence of KJ1R5, showed higher similarities to those of a group consisting of several Chryseobacterium strains with 95.2, 95.2, and 95,1％ similarity to C. defluvii, Chryseobacterium sp. FR2, and C. scophthalmum, respectively, In addition, Halounella gailinarum, Bergeyella zoohelcum, and Riemerella anatipestifer are another group for KJ1R5, with 94.1, 89.7, and 87.2％ similarities, respectively When identification of the antagonistic bacterium, KJ1R5, was conducted using BIOLOG system, the strain KJ1R5, was identified as Flavobacterium tirrenicum (similarity； 0.75％). Fatty acid profiles of the strain KJ1R5, were composed mainly of iso-17：0 w9c and iso-15：0 and identified as Chryseobacterium balustinum (similarity 0.524％). KJ1R5, was Gram-negative, regular short rods ranging from 0.8 $\mu\textrm{m}$ to 1.0 $\mu\textrm{m}$ and had no flagella. Phenotypic characterization of the antagonistic bacterium indicated that KJ1R5, were included in the genus Chreseobacterium, which belongs to the family Flavobacteriaceae. The strain was distinguished from these six existing species. These results indicated that strain might be placed as a new species in the genus Chryseobacterium.