FIG 6 .

Killing indices (KIs) of run 2 were compared to those of run 1 (left) or KIs of multiple runs to geometric mean KIs (middle and right) to examine intralaboratory reproducibility of SBA for S. flexneri 2a (A, B, and C), S. flexneri 3a (D, E, and F) and S. sonnei (G, H, and I). (A, D, and G) The experiments whose results are shown used the same reagents. (B, E, and H) The experiments whose results are shown used 3 different bacterial stocks. Bacterial stocks were kept frozen at −80°C for various periods (solid black circles, ~3 months old; solid blue triangles, ~1 year old; and solid red circles, ~4 years old). (C, F, and I) The experiments whose results are shown used 5 different complement lots. Five different complement lots from Pel-Freez are shown with different colored symbols. The line of identity (solid line) is shown along with dotted lines indicating 2-fold deviations from identity. The results shown in the middle and right panels suggest that KIs generally differ by less than 2-fold regardless of target bacterium or complement lot and that KIs are offset for all samples tested with each lot of bacteria or complement.