Evaluation of BacT/ALERT plastic culture bottles for use in testing pooled whole blood-derived leukoreduced platelet-rich plasma platelets with a single contaminated unit

BACKGROUND: In certain countries, whole blood-derived platelet (PLT)-rich plasma PLTs can only be pooled within 4 hours of transfusion. One prerequisite for prestorage pooling is the ability to detect low levels of bacteria from a single unit (approx. 10 colony-forming units [CFUs]/mL) once pooled (10/6 approx. 2 CFUs/mL). This study evaluated the BacT/ALERT (bioMerieux) for detection of bacteria in 1 unit of a 6-unit pool. STUDY DESIGN AND METHODS: Bacillus cereus, Clostridium perfringens, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Streptococcus viridans, and Propionibacterium acnes were inoculated into single PLT units (target, 10 and 100 CFUs/mL; mean recovered, 5 and 92 CFUs/mL) and then pooled with 5 sterile units. Four milliliters was inoculated into both plastic aerobic and anaerobic bottles, and 0.5 mL was plated (10 sets). RESULTS: All cases were detected when the single unit had at least 6 CFUs per mL. With B. cereus (<= 2 CFUs/mL), all bottles were reactive. With K. pneumoniae and S. viridans (<= 3 CFUs/mL), all samples were detected with a two-bottle set, but not all bottles were reactive. With S. marcescens (< 2 CFUs/mL), only 7 of the 10 sets were reactive. With C. perfringens (0.2 CFUs/mL), only 3 of 10 samples were detected in the anaerobic bottles. CONCLUSIONS: This study evaluates the use of the BacT/ALERT system for detection of bacteria in PLT pools. Overall, the BacT/ALERT detected all contaminated pooled PLTs when the single inoculated unit had a calculated or recovered concentration at least 3 CFUs per mL with 10 different species of bacteria. Low recovered concentrations (<= 2 CFUs/mL) were, in some cases, only detected with a two-bottle set.