Clostridium perfringens in apheresis platelets: an unusual contaminant underscores the importance of clinical vigilance for septic transfusion reactions (CME)

Background Posttransfusion sepsis is typically caused by aerobic bacteria in apheresis platelets ( PLTs ) that escape detection by routine quality control cultures performed on every donation before components are distributed. We report the first case to implicate an anaerobic isolate, Clostridium perfringens , in apheresis PLTs and investigate its detection in vitro by approved tests. Study Design and Methods The C. perfringens strain was inoculated at high (10‐100 colony‐forming units [ CFUs ]/ mL ) or low (1‐10 CFUs / mL ) concentrations into apheresis PLTs and evaluated for growth over 5 to 7 days by qualitative plate cultures, culture‐based assays ( BacT / ALERT 3 D ), and rapid ( PLT PGD ) tests. Results C. perfringens grew in only 3 of 8 apheresis PLT units after inoculation at either high (2 units) or low (1 unit) concentrations. The PGD test detected the isolate after 5 days in 1 unit with 4.7 × 10 5 CFUs / mL but failed at five other time points in units with greater than 10 5 CFUs / mL . Conclusion C. perfringens demonstrated variable growth in spiked PLTs and was not consistently detected by a rapid test even when high levels of contamination were present. The case underscores the importance of direct observation during transfusion, appropriate clinical management, and immediate reporting of suspected septic reactions to the blood center.