Table 3.

Effects of plasmids that carry the lasI orrhlI gene or both the lasI and rhlIgenes on the virulence of P. aeruginosa JP2

StrainNo. of mice dead/total (% mortality)aAvg % mortalityb
Expt 1Expt 2Expt 3
PAO17/7 (100)5/6 (83.3)6/6 (100)94.3
JP2/pSW200c0/5 (0)1/5 (20)0/5 (0)6.7
JP2/pLASI-2c4/5 (80)3/5 (60)4/5 (80)73.3
JP2/pJPP45c2/5 (40)3/5 (60)2/5 (40)46.7
JP2/pJPP42c4/5 (80)5/5 (100)5/5 (100)93.3
  • 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. The mortality among mice infected with each strain was determined at 48 h post burn infection as previously described (34). Three separate experiments were conducted with each strain.

  • b The average percent mortality of three independent experiments is shown.

  • 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.