A-292 Comparison of the Neutralizing Capabilities of Two Blood Culture Bottles for IgG and TRF

Abstract Background The human body has a powerful immune system that responds to pathogenic invasion. When pathogens invade, immune proteins in the blood, such as IgG and transferrin (TRF), participate in immune responses to eliminate these intruders. However, these immune proteins can reduce the positivity rate of blood cultures. Autobio blood culture bottle contains resin and immune factor scavengers to mitigate these negative effects. Methods A total of 5 mL of mixed serum was added to Autobio FA blood culture bottle and bioMérieux FA Plus blood culture bottle. Autobio FA was incubated in the Autobio BC120, while bioMérieux FA Plus was incubated in BACT/ALERT 3D 240 system. A biochemical reagent kit was used to measure the remaining IgG and TRF levels at 0h, 2h, 4h, 6h, and 22h in Autobio FA and bioMérieux FA Plus at different time points. Results IgG content in the Autobio FA decreased from 212.46 mg/dL to 201.12 mg/dL over 0-24 hours, showing a reduction of only 5.34% after 24 hours. In contrast, IgG content in bioMérieux FA Plus decreased from 217.44 mg/dL to 211.99 mg/dL over the same 0-24 hour period, with a reduction of 2.51% after 24 hours. For TRF, Autobio FA content decreased from 0.43 g/L to 0.40 g/L over 0-24 hours, showing a decrease of 6.98% after 24 hours. Meanwhile, TRF content in bioMérieux FA Plus decreased from 0.45 g/L to 0.41 g/L, with an 8.89% reduction after 24 hours. Conclusion The results indicate that both Autobio FA and bioMérieux FA Plus have limited adsorption effects on IgG and TRF. The decrease in IgG content in the Autobio FA over 24 hours was slightly greater than that in bioMérieux FA Plus, whereas the opposite was observed for TRF content. The current low blood culture positivity rate may be related to the inability of commercially available blood culture bottles to effectively reduce these immune factors. Manufacturers need to further explore methods to reduce such immune factors in blood culture bottles.