Biomaterial Database

The Attenuation Mechanism and Live Vaccine Potential of a Low-Virulence Edwardsiella ictaluri Strain Obtained by Rifampicin Passaging Culture. 2023

Shuyi Wang, and Jingwen Hao, and Jicheng Yang, and Qianqian Zhang, and Aihua Li

State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P.R. China.

The rifampicin-resistant strain E9-302 of Edwardsiella ictaluri strain 669 (WT) was generated by continuous passage on BHI agar plates containing increasing concentrations of rifampicin. E9-302 was attenuated significantly by 119 times to zebrafish Danio rerio compared to WT in terms of the 50% lethal dose (LD50). Zebrafish vaccinated with E9-302 via intraperitoneal (IP) injection at a dose of 1 × 103 CFU/fish had relative percentage survival (RPS) rates of 85.7% when challenged with wild-type E. ictaluri via IP 14 days post-vaccination (dpv). After 14 days of primary vaccination with E9-302 via immersion (IM) at a dose of 4 × 107 CFU/ml, a booster IM vaccination with E9-302 at a dose of 2 × 107 CFU/ml exhibited 65.2% RPS against challenge with wild-type E. ictaluri via IP 7 days later. These results indicated that the rifampicin-resistant attenuated strain E9-302 had potential as a live vaccine against E. ictaluri infection. A previously unreported amino acid site change at position 142 of the RNA polymerase (RNAP) β subunit encoded by the gene rpoB associated with rifampicin resistance was identified. Analysis of the whole-genome sequencing results revealed multiple missense mutations in the virulence-related genes esrB and sspH2 in E9-302 compared with WT, and a 189 bp mismatch in one gene, whose coding product was highly homologous to glycosyltransferase family 39 protein. This study preliminarily explored the molecular mechanism underlying the virulence attenuation of rifampicin-resistant strain E9-302 and provided a new target for the subsequent study of the pathogenic mechanism of E. ictaluri.

UI	MeSH Term	Description	Entries
D004756	Enterobacteriaceae Infections	Infections with bacteria of the family ENTEROBACTERIACEAE.	Enterobacterial Infections,Cronobacter Infections,Infections, Enterobacteriaceae,Infections, Enterobacterial,Cronobacter Infection,Enterobacteriaceae Infection,Enterobacterial Infection,Infection, Cronobacter,Infection, Enterobacteriaceae,Infection, Enterobacterial,Infections, Cronobacter
D005393	Fish Diseases	Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).	Disease, Fish,Diseases, Fish,Fish Disease
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001428	Bacterial Vaccines	Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.	Bacterial Vaccine,Bacterin,Vaccine, Bacterial,Vaccines, Bacterial
D012293	Rifampin	A semisynthetic antibiotic produced from Streptomyces mediterranei. It has a broad antibacterial spectrum, including activity against several forms of Mycobacterium. In susceptible organisms it inhibits DNA-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis. Rifampin is bactericidal, and acts on both intracellular and extracellular organisms. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1160)	Rifampicin,Benemycin,Rifadin,Rimactan,Rimactane,Tubocin
D014613	Vaccines, Attenuated	Live vaccines prepared from microorganisms which have undergone physical adaptation (e.g., by radiation or temperature conditioning) or serial passage in laboratory animal hosts or infected tissue/cell cultures, in order to produce avirulent mutant strains capable of inducing protective immunity.	Attenuated Vaccine,Vaccines, Live, Attenuated,Attenuated Vaccines,Vaccine, Attenuated
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity
D015027	Zebrafish	An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. Zebrafish is a model organism for drug assay and cancer research.	Brachydanio rerio,Danio rerio,B. rerio,D. rerio,Zebra Fish,Zebra Fishes,Zebra danio,Zebrafishes,D. rerios,Fishes, Zebra,Zebra danios,danio, Zebra
D020610	Edwardsiella ictaluri	A species of EDWARDSIELLA distinguished by its nonmotility. (From Bergey's Manual of Determinative Bacteriology, 9th ed)