Fig. 4
Analysis of susceptibility to growth inhibition by zinc intoxication based on isolation source. Group B Streptococcus (GBS) strains isolated from recto-vaginal swabs (Vaginal/Rectal, circles), early onset disease in neonates (EOD, squares), late onset disease in neonates (LOD, triangles), or blood/sepsis in adults (Blood/Sepsis, inverted triangles) were grown in medium alone (Medium Alone) or increasing concentrations of zinc chloride (125 μM, 250 μM, 500 μM, 750 μM, 1000 μM, 2500 μM, 5000 μM). Bacterial growth was measured at 24 h post-inoculation as an optical density at 600 nm absorbance (OD600). At 250, 500, 750, 1000 and 2500 μM concentrations of zinc, rectovaginal strains of GBS (circles) exhibited greater growth inhibition than strains isolated from early onset disease in neonates (squares), as determined by one-way ANOVA with Tukey’s post hoc multiple correction (*P < 0.05, and **P < 0.01, n = 3 biological replicates)