Related Experiment Video
Updated: May 16, 2026
Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS
Published on: July 11, 2016
Identification and virulence of Chryseobacterium indologenes isolated from diseased yellow perch (Perca flavescens)
J W Pridgeon1, P H Klesius, J C Garcia
1Aquatic Animal Health Research Unit, USDA-ARS, Auburn, AL 36832, USA. julia.pridgeon@ars.usda.gov
Aim:
To identify pathogen of diseased yellow perch and determine their virulence.
Methods And Results:
Fifteen Gram-negative bacterial isolates were recovered from the skin lesions of diseased yellow perch (Perca flavescens). Based on API 20NE test, ten isolates were found to share 67.2-99.9% homologies with Chryseobactertium indologenes. Based on fatty acid methyl ester analysis, 13 isolates were found to share similarities with C. indologenes and other species of Chryseobacterium. Based on sequencing results of partial 16S rRNA gene, 13 isolates shared 99% identities (e value = 2e-50) with the 16S rRNA sequence of C. indologenes (GenBank HQ259684). Based on the 16S-23S rRNA intergenic spacer region (ISR) sequence, the 13 isolates shared 88% identity (e value = 1e-165) with the 16S-23S ISR sequence of C. indologenes (GenBank EU014570). T-coffee multiple sequence alignment revealed that the partial 16S rRNA or the 16S-23S ISR sequence of the 13 isolates shared 100% identity with each other. When healthy yellow perch were exposed to the 15 isolates by bath immersion (c. 6 × 10(7) CFU ml(-1) for 1 h), only C. indologenes isolates killed 10-20% of fish, whereas other isolates were avirulent. When yellow perch were exposed to C. indologenes by intraperitoneal injection, mortality was dose dependent, with LD(50) and LD(95) values of 1.5 × 10(8) and 3.2 × 10(8) CFU per fish, respectively.
Conclusions:
Chryseobactertium indologenes could be pathogenic to yellow perch.
Significance And Impact Of The Study:
This is the first report on the isolation of C. indologenes from diseased yellow perch. Virulence studies suggested that C. indologenes could become pathogenic to yellow perch.
Insights
Chryseobacterium indologenes was identified as a pathogen in diseased yellow perch. Virulence studies confirmed its ability to cause mortality in yellow perch, indicating its pathogenic potential.
Area of Science:
- Aquatic Animal Health
- Fish Pathology
- Bacteriology
Background:
- Diseased yellow perch (Perca flavescens) exhibited skin lesions.
- Identifying the causative agent and its virulence is crucial for understanding fish diseases.
Purpose of the Study:
- To isolate and identify the bacterial pathogen responsible for disease in yellow perch.
- To determine the virulence of the identified pathogen.
Main Methods:
- Bacterial isolates from skin lesions were identified using API 20NE, fatty acid methyl ester analysis, and 16S rRNA gene sequencing.
- Virulence was assessed by exposing healthy yellow perch to isolates via bath immersion and intraperitoneal injection.
Main Results:
- Fifteen Gram-negative bacterial isolates were recovered; thirteen were identified as Chryseobacterium indologenes.
- C. indologenes isolates caused 10-20% mortality in bath immersion trials.
- Intraperitoneal injection of C. indologenes resulted in dose-dependent mortality, with LD50 and LD95 values determined.
Conclusions:
- Chryseobacterium indologenes is identified as a potential pathogen of yellow perch.
- This study is the first to report the isolation of C. indologenes from diseased yellow perch and demonstrates its virulence.
More Related Videos
09:44Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
Published on: December 23, 2022
09:34Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species
Published on: November 8, 2016
