Roseobacter group probiotics exhibit differential killing of fish pathogenic Tenacibaculum species

Jens Edward Tesdorpf, Aileen Ute Geers, Mikael Lenz Strube, Lone Gram, Mikkel Bentzon-Tilia*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

147 Downloads (Pure)


Fish pathogenic bacteria of the Tenacibaculum genus are a serious emerging concern in modern aquaculture, causing tenacibaculosis in a broad selection of cultured finfish. Data describing their virulence mechanisms are scarce and few means, antibiotic treatment aside, are available to control their proliferation in aquaculture systems. We genome sequenced a collection of 19 putative Tenacibaculum isolates from outbreaks at two aquaculture facilities and tested their susceptibility to treatment with tropodithietic acid (TDA)-producing Roseobacter group probiotics. We found that local outbreaks of Tenacibaculum can involve heterogeneous assemblages of species and strains with the capacity to produce multiple different virulence factors related to host invasion and infection. The probiotic Phaeobacter piscinae S26 proved efficient in killing pathogenic Tenacibaculum species such as T. maritimum, T. soleae, and some T. discolor strains. However, the T. mesophilum and T. gallaicum species exhibit natural tolerance towards TDA and are hence not likely to be easily killed by TDA-producing probiotics. Tolerance towards TDA in Tenacibaculum is likely involving multiple inherent physiological features pertaining to electron and proton transport, iron sequestration, and potentially also drug efflux mechanisms, as genetic determinants encoding such features were significantly associated with TDA tolerance. Collectively, our results support the use of TDA-producers to prevent tenacibaculosis, however, their efficacy is likely limited to some Tenacibaculum species.
Original languageEnglish
Article numbere02418-21
JournalApplied and Environmental Microbiology
Issue number6
Publication statusPublished - 2022


  • Tenacibaculum
  • Fivobacteria
  • Roseobacters
  • Probiotics
  • Aquaculture
  • Tropodithietic acid


Dive into the research topics of 'Roseobacter group probiotics exhibit differential killing of fish pathogenic Tenacibaculum species'. Together they form a unique fingerprint.

Cite this