Clustal analysis of Qnr proteins. Characterized and predicted Qnr proteins were clustered. The tree was calculated using the average percentage of identity. Other two members of the pentapeptide repeat family with proven resistance to fluoroquinolones, MfpA from Mycobacterium tuberculosis and McbG from Escherichia coli, were included in the analysis, but are not shown because they plotted out of the Qnr tree. Chromosomally-encoded Qnr proteins are highlighted in bold. The position of the SmQnr protein from S. maltophilia as a member of the QnrB cluster is highlighted with a square. Novel Qnr proteins are named according to the species where they are originated: AhQnr (Aeromonas hydrophila), AsQnr (Aeromonas salmonicida), MsQnr (Moritella sp), SprQnr (Serratia proteamaculans), SbeQnr (Shewanella benthica), SfrQnr (Shewanella frigidimarina), SliQnr (Shewanella loihica), SpaQnr (Shewanella pealeana), SseQnr (Shewanella sediminis), SwoQnr (Shewanella woodyi), SmQnr (Stenotrophomonas maltophilia), PsQnr (Psychromonas), ValQnr (Vibrio alginolyticus), VanQnr (Vibrio angustum), VfQnr (Vibrio fischeri), VhQnr (Vibrio harveyi), VshQnr (Vibrio shilonii), VspQnr (Vibrio splendidus), VvQnr (Vibrio vulnificus).