Format

Send to

Choose Destination
J Fish Dis. 2019 May;42(5):643-655. doi: 10.1111/jfd.12964. Epub 2019 Feb 4.

Molecular characterization and pathogenicity of Francisella noatunensis subsp. orientalis isolated from cultured tilapia (Oreochromis sp.) in Taiwan.

Author information

1
Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan.
2
Animal Protection Office, Taoyuan City, Taiwan.
3
Southern Taiwan Fish Diseases Research Center, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan.
4
International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan.
5
Research Center for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan.

Abstract

Francisella noatunensis subsp. orientalis is a causative agent of systemic granulomatous disease in tilapia. The present study was designed to understand the genetic and phenotypic diversities among Taiwanese Fno isolates obtained from tilapia (n = 17) and green Texas cichlid (Herichthys cyanoguttatus) (n = 1). The enzymatic profiles of the isolates were studied using the API ZYM system. Phylogenetic tree analysis of the 16S rRNA and housekeeping gene and pulsed-field gel electrophoresis (PFGE) were carried out to determine the genotypic characters of all isolates. The phylogenetic tree showed similarity of 99%-100% nucleotide sequences of 16S rRNA and housekeeping genes compared to the Fno references genes from GenBank database. Comparatively, the results revealed an identical profile of enzymatic and PFGE pattern which was distincted from that of F. philomiragia. To understand the pathogenicity, the isolates were intraperitoneal injected to tilapia the gross lesions were observed concomitant with natural outbreak. Median lethal dose upon Nile tilapia and red tilapia were 9.06 × 103 CFU/fish and 2.08 × 102 CFU/fish, respectively. Thus, our data provide understanding the epidemiology of Taiwanese Fno isolates, and help in development of future control and prevention.

KEYWORDS:

Francisella noatunensis susbsp. orientalis; Oreochromis sp; PFGE; genotype; pathogenicity; phenotype

PMID:
30715744
DOI:
10.1111/jfd.12964
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center