To begin understanding the individual roles of hmv and CPS within the context of the host with the mutants identified here, we evaluated the competitive fitness of the six representative targeted gene deletion mutants (ΔaceE, ΔsdhA, ΔpurA, ΔgalU, Δwza, and ΔcsrD) in vitro in LB and BALF, as well as in vivo in a murine model of pneumonia. The gene discussed is CAD; the disease is pneumonia.