Different Phenotypes of Mature Biofilm in Flavobacterium psychrophilum Share a Potential for Virulence That Differs from Planktonic State

• DOI: 10.3389/fcimb.2017.00076
• Publication Date: 2017-03-15T03:37:51Z
• Authors: Héctor A. Levipan; Ruben Avendaño-He...
• Keywords: 0301 basic medicine; bacterial cold water disease; rainbow trout fry syndrome; Virulence; Gene Expression Profiling; virulence factors; Microbiology; Flavobacterium; gene transcription; 03 medical and health sciences; Phenotype; atlantic salmon; Oncorhynchus mykiss; Biofilms; Flavobacterium psychrophilum; biofilm formation; 14. Life underwater

Flavobacterium psychrophilum is the etiological agent of bacterial coldwater disease and rainbow trout fry syndrome in salmonid aquaculture worldwide. However, there have been few studies into capacity F. to form biofilms how these cellular accretions differ from planktonic cells or they affect potential virulence. We evaluated biofilm formation by three Chilean isolates (LM-02-Fp, LM-06-Fp LM-13-Fp) two non-Chilean strains (JIP02/86 NCMB1947T), compared states obtain insights expression differences virulence- biofilm-related genes (VBRGs). Our findings are based on scanning confocal laser microscopy (SCLM) LIVE/DEAD staining, enzymatic reactions, reverse transcription-quantitative PCR (RT-qPCR) encoding putative virulence factors, transcriptomes (RNA-Seq). The LM-02-Fp NCMB1947T were strongest weakest producers, respectively. strong-biofilm producer showed different physiological cell distributed layers mature biofilms, whereas consisted arranged a monolayer. WGA-binding exopolysaccharides would be main components their corresponding extracellular matrices. Transcriptomes clustered state (biofilm versus planktonic) rather than strain, indicating important state-dependent gene expression. Analysis differentially expressed between identified VBRGs involved polysaccharide biosynthesis, lateral transfer, membrane transport (e.g. for drugs Fe3+), sensory mechanisms, adhesion, indicated that about 60 % 100 processes was significantly upregulated state. Conversely, motility-related not identified, lower fraction proteolysis-related (33 %) biofilms. In summary, produce phenotypes show global transcriptional activity differs counterparts. Also, share genetic transcriptionally enhanced with respect free-living cells. results suggest lifestyle acts as reservoir given set recommend deeper understanding which could help prevent recurring infections farms.