Abstract: Objectives To retrospectively analyze the bacterial results of 405 392 bags of apheresis platelets detected by Shanghai Blood Center, evaluate the occurrence and control of bacterial contamination of apheresis platelets in Shanghai, and provide basis for formulating bacterial contamination detection strategies and preventive measures. Methods From January, 2017 to December, 2023, the apheresis platelets collected at least 24 hours apart were sampled from the mother bag to the retention bag, and inoculated in aerobic culture bottles. The automatic microbial culture system was used for bacterial screening, and the positive bacterial data were statistically analyzed. Results From January 2017 to December 2023, a total of 423 initial positive samples were detected by using three culture systems. Through statistical analysis, the initial positive rate was 10.43×10^-4, the confirmed positive rate was 1.95×10^-4, the uncertain positive rate was 1.33×10^-4, and the inconsistent positive rate was 0.12×10^-4. 32 species and 151 strains of bacteria were detected by MALDI-TOF MS Among the positive results, Staphylococcus epidermidis, Staphylococcus cephalus and Staphylococcus hominis accounted for a high proportion. Among the uncertain results, Bacillus brevis, Staphylococcus epidermidis and Staphylococcus capitis account for a high proportion. Among the inconsistent positive results, Bacillus amyloliquefaciens, Streptococcus Constellation, Autolytic bacteria and Paecilomyces fortis were the main ones. Bacillus brevis, Bacillus megaterium, Bacillus subtilis, Bacillus Mojave and Staphylococcus hominis account for a high proportion in the false positive results. Bacillus cereus, Lactococcus gasseri and Bacillus licheniformis were the main bacteria detected within 12 h after the initial positive report. The main bacteria detected within (12~24) h were Staphylococcus epidermidis, Streptococcus agalactiae. Among the confirmed positive bacteria, the number of skin conditional pathogens group was significantly higher than that of environmental conditional pathogens and common pathogens group, and the difference was statistically significant (P<0.05). Conclusion By using automatic blood culture system to detect bacteria in apheresis platelets collected in Shanghai from 2017 to 2023, 405 392 cases of detection data were retrospectively analyzed, and relatively reliable and complete data of bacterial screening of apheresis platelets collected in large samples were obtained. Staphylococcus epidermidis, Staphylococcus cephalus and Staphylococcus hominis accounted for a high proportion of positive results. The results showed that there was no statistical difference in bacterial positive detection results of platelet collected by three culture devices, and Bact/Alert 3D and Autobio culture systems were in operation. BACTEC system has advantages in sensitive detection. Relevant units can select relevant equipment according to application scenarios.

Key words: Apheresis platelets, Bacterial contamination, Automated microbial inoculation system, Blood safety