FIG 5.

Inactivation of rpiRc results in reduced survival (A) and increased bacterial burden (B and C) of S. aureus in a murine pneumonia model. Wild-type S. aureus strain SA564, the rpiRc deletion mutant (SA-rpiRc), the rpiRc mutant carrying the cis-integrated plasmid pEC4-rpiRc for complementation (SA-rpiRc_rpiRc), and the sarA single (SA-sarA) and rpiRc double (SA-sarA rpiRc) mutants were grown to exponential growth phase (2 h), washed, and intranasally administered to 8- to 9-week-old C57/BL6N mice. (A) The survival of mice using an infectious dose of 2.5 × 10⁸ CFU was monitored. (B and C) After infection with 10⁸ CFU, the bacterial loads in BAL samples (B) and lung tissue homogenates (C) were determined at 24 h postinfection. Each symbol represents an individual animal, and the mean values per group are depicted by horizontal lines. For statistical analysis, nonparametric Mann-Whitney tests were performed (*, P < 0.05; **, P < 0.01).