BALB/c mice are challenged via intraperitoneal (IP) injection with S. aureus strains in 3% mucin as previously described by Fattom et al. Mice are monitored for morbidity and mortality twice a day for 14 days. The hog mucin model has the advantage of a broadened dose response range allowing incremental increases in the challenge dose to differentiate between different therapeutic agents (see typical dose response in Figure 2A). We have determined the LD50 in this model for various strains. Lethality occurs typically within 24-48 hours post infection. Figure 2B shows a meta-analysis of study results using an experimental vaccine (n=115) versus control (n=28) in the S. aureus bacteremia model.