Virulence of IgaA-deficient mutants of serovar Typhimurium having distinct activation levels of the RcsCDB system

Strain mixtureStatus of the Rcs systemaCompetitive indexb
MD0835-J1 [igaA2::KIXX Δ(apbE′-rcsC′)] × WTInactive0.63 ± 0.110.82 ± 0.12
MD0842-J4 [igaA2::KIXX rcsC67′] × WTIntermediate0.65 ± 0.030.92 ± 0.11
MD0855-J10 [igaA2::KIXX Δ(ompC′-micF)] × WTHigh0.06 ± 0.020.07 ± 0.01
  • a As indicated by the relative levels of expression of the wcaH21::lacZ transcriptional fusion in the MD0835-J1, MD0842-J4, and MD0855-J10 strains (see reference 42).

  • b Competitive index values were calculated as described previously (2) after intraperitoneal challenge of BALB/c mice with a dose of 2 × 105 CFU per strain. Liver and spleen were extracted at 48 h postinfection. Shown are the medians and standard deviations corresponding to results from two independent experiments.