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. 2018 Jul 5;8:10225. doi: 10.1038/s41598-018-28583-8

Figure 2.

Figure 2

Influence of anticoagulants on survival of N. meningitidis strains (and N. lactamica) in whole blood infection. (a) Survival curves of various N. meningitidis strains and one N. lactamica strain (strain characteristics are in Supplementary Table S1; strains in red were isolated from IMD cases and strains in blue from asymptomatic carriers) in whole blood anticoagulated with different anticoagulants (see legend). Blood was drawn using monovettes containing the indicated anticoagulants from adult healthy donors with no history of meningococcal disease or vaccination and infected with 106 CFU/ml of the indicated bacterial strains. At indicated time points, viable bacteria were enumerated after plating serial dilutions onto blood agar plates and plotted as log10 of CFU/ml. Limit of detection was 500 CFU/ml (log10 = 2.7), values below detection limit were plotted as 100 CFU/ml (log10 = 2). Plotted are means ± SEM of results from 6–9 independent experiments (donors). As positive control, bacteria were incubated in BHI instead of blood. (b) Area under curve analysis of the growth curves from the individual experiments (donors). The detection limit is calculated from the detection limit in (A) (log10 of CFU/ml set to 2 for negative samples) multiplied by 6 h. *, **, ***, **** denote P < 0.05, 0.01, 0.005, 0.0005 in one-way ANOVA applying Bonferrroni’s post hoc test. ns, not significant. Please note that the arrangement of plots, grouped by capsule characteristics and/or sequence type of the infection strain as highlighted by the coloured boxes, is continuous throughout this study.