Resistance-nodulation-division efflux pump acrAB is modulated by florfenicol and contributes to drug resistance in the fish pathogen Piscirickettsia salmonis

Rodrigo Sandoval, Cristian Oliver, Sharin Valdivia, Karla Valenzuela, Ronie E. Haro, Patricio Sánchez, Víctor H. Olavarría, Paulina Valenzuela, Rubén Avendaño-Herrera, Alex Romero, Juan G. Cárcamo, Jaime E. Figueroa, Alejandro J. Yáñez

Research output: Contribution to journalLetterpeer-review

26 Citations (Scopus)

Abstract

Piscirickettsia salmonis is a fastidious intracellular pathogen responsible for high mortality rates in farmed salmonids, with serious economic consequences for the Chilean aquaculture industry. Oxytetracycline and florfenicol are the most frequently used antibiotics against P. salmonis, but routine use could contribute to drug resistance. This study identified differentiated florfenicol susceptibilities in two P. salmonis strains, LF-89 and AUSTRAL-005. The less susceptible isolate, AUSTRAL-005, also showed a high ethidium bromide efflux rate, indicating a higher activity of general efflux pump genes than LF-89. The P. salmonis genome presented resistance nodulation division (RND) family members, a family containing typical multidrug resistance-related efflux pumps in Gram-negative bacteria. Additionally, efflux pump acrAB genes were overexpressed in AUSTRAL-005 following exposure to the tolerated maximal concentration of florfenicol, in contrast to LF-89. These results indicate that tolerated maximum concentrations of florfenicol can modulate RND gene expression and increase efflux pump activity. We propose that the acrAB efflux pump is essential for P. salmonis survival at critical florfenicol concentrations and for the generation of antibiotic-resistant bacterial strains.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalFEMS Microbiology Letters
Volume363
Issue number11
DOIs
Publication statusPublished - 1 Jun 2016

Keywords

  • AcrAB efflux pump
  • Antibiotic resistance
  • Florfenicol
  • Piscirickettsia salmonis
  • RND efflux pump
  • SRS

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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