Table 4.

Effects of the lasI or rhlI gene or both the lasI and rhlI genes on the spread ofP. aeruginosa quorum-sensing mutant JP2 within burned skin at 8 h post burn infection

StrainMean no. of CFUa (± SEM) recovered from:
Inoculation sitebDistant siteb
PAO11.8 × 106 ± 7.0 × 1053.0 × 105 ± 7.6 × 104
PAO-R11.0 × 106 ± 2.8 × 1050.0
JP2/pSW200c5.3 × 105 ± 7.2 × 1040.0
JP2/pLASI-2c8.3 × 105 ± 2.8 × 1044.6 × 104 ± 1.4 × 103
JP2/pJPP45c3.4 × 105 ± 8.5 × 1045.4 × 103 ± 2.4 × 103
JP2/pJPP42c9.2 × 105 ± 8.2 × 1043.2 × 105 ± 5.2 × 104
  • a A total of 2 × 102 to 3 × 102 CFU of each strain was injected subcutaneously at the burn site immediately after burning. The mice were burned and then inoculated with each strain as described in Materials and Methods. At 8 h post burn infection, the mice were euthanized and two separate skin sections were obtained. The number of CFU in each section was determined as described in Materials and Methods.

  • b A section (5 by 5 mm) of burned-and-infected skin at the site of inoculation was isolated and homogenized, and the number of CFU was determined (the inoculation site). A similar section (5 by 5 mm) was obtained from the burned-and-infected skin at a distance of 15 mm from the inoculation site (distant site).

  • c Plasmid pSW200 is a cloning vector (negative control), plasmid pLASI-2 carries a DNA fragment containing the intactlasI gene, plasmid pJPP45 carries a DNA fragment containing the intact rhlI gene, and plasmid pJPP42 carries a DNA fragment containing the intact lasI and rhlIgenes.