S100A9 and infection: To evaluate if the importance of GpmA during infection is driven by host restriction of Mn availability, CP-deficient (C57BL/6 S100A9-/-) mice, which do not remove Mn from liver abscesses [25, 29], were infected with wild type bacteria, ΔgpmA or ΔgpmI. Relative to wild type mice, the CP-deficient mice infected with ΔgpmA had increased bacterial burdens, indicating that the importance of GpmA during infection is driven by host-imposed Mn limitation.