Survival of selected L. monocytogenes (A) and S. aureus (B) strains in human whole blood. Strains were adjusted to 1.0 × 103 CFU/ml, mixed 1:3 with human whole blood, and incubated at 37°C. E. coli MG1655 was used as a positive control for neutrophil killing. Bars represent standard deviations of duplicate observations. Graphs are representative of two independent experiments. Arrows indicate that cell numbers were below the detection limit (1.0 × 101 CFU/ml).