TABLE 6.

Summary of mutations in regions associated with antimicrobial susceptibility and QS

LocusLES isolate(s)aMutation(s)Comment(s)Relevant reference(s)
AntimicrobialSusceptibility
    mexRLES400 and LES431R83→CMutation not reported previously13, 24, 32, 57
    mexA-R intergenicLES400 and LES431Ribosome-binding site for mexA AGGA → AGGGPrevious report of mutation in the ribosome-binding site leading to down-regulation (AGGA → CGGA)13
    ampRLES400 and LES431D135→G;Previous report of D135→N mutation in strain with high levels of β-lactamase activity; disruption of AmpR translation2
    ampR-C intergenicLES400 onlyATG→TTG (start codon) −71 with respect to the start codon of ampG5 C→TEffect of mutation is unknown
    ampCLES400 onlyATG→ATT (start codon)Disruption of AmpC translation
    ampDLES400 and LES431G148→A and S175→LSame substitutions observed previously in strains with high AmpC activity but discounted as cause of up-regulation2, 19
    PA4523-ampD intergenicLES400 and LES43176 bp upstream of the ampD start codon; A→CEffect of mutation is unknown
    mexZLES400 and LES431Q164→termination (CAA→TAA)Similar though not identical truncations associated with aminoglycoside resistance among CF isolates49
QS related
    rhlR-rhlI intergenicLES400 and LES43130 bp upstream of the rhlI start codon, TTTTTTTTCTC → TTTTTTT-CTCEffect of mutation is unknown
    rhlBLES400 and LES431Downstream of P3 (one rhlR transcription start site), AGGGAGGGGGATGCTC → AGGGAGGGGGATGCGCEffect of mutation is unknown
    lasRLES400 onlyRepetition of GGTGCTC leading to divergence from G123 onwardLoss of the HTH DNA-binding LuxR motif
    lasRLES430 onlyDeletion of GTGGATGCTC leading to divergence from position W152 onwardLoss of the HTH DNA-binding LuxR motif
    lasRLESB44 onlyInsertion of GAAG leading to divergence from position I35 onwardLoss of most of LasR
    rsaL-lasI intergenicLES400 and LES431In between the lux-box-like sequence NNCT-(N)12-AGNN and the lasI start codon, located 6 bp away from the lux box-like sequenceEffect of mutation is unknown
    PA2587 and gacA intergenicLES400 and LES4316 bp different from PAO1; nearest mutation was 160 bp upstream from the gacA start codonEffect of mutation is unknown
  • a LES isolates refers to LES400 and LES431 only, with the exception of the mutations found in the lasR gene of isolates LES430 and LESB44.