FIG 4 .

Neutrophil killing assays of CSF and blood Salmonella isolates were performed following exposure to antibiotic-free medium (untreated) or pretreatment with 1/4 MIC of ceftriaxone (CRO), 1/4 MIC of ciprofloxacin (CIP), or 1/4 MIC of chloramphenicol (CM). CRO sensitizes Salmonella enterica serotype Newport to neutrophil killing. Data are plotted as mean ± SEM and represent the percentage of bacterial survival remaining following 15 min of neutrophil exposure compared to the initial inoculum. **, P < 0.005, and n.s., no statistical significance, by two-way analysis of variance (ANOVA) and comparing pretreated bacteria to untreated bacteria.