Comparison of Sensitivity of Tests for Detecting Bacterial Contamination in Platelet Concentrates

Background: The demand for platelet concentrates has increased for patients with hemato-oncologic diseases as well as for patients with chronic diseases. As platelet concentrates are preserved at , the chance of bacterial contamination exposure is increased, which can cause fatal outcomes. We evaluated various methods for detecting bacterial contamination in platelet concentrates. Methods: 0.5 MacFarland standard solutions were prepared using the Staphylococcus aureus ATCC 25923 & Escherichia coli ATCC25922 strains. The platelet concentrates were inoculated with various concentrations ( CFU/mL) of bacteria and then gram staining, plate culture, broth culture and 16s RNA were used to detect bacteria. Results: The gram stain method was unable to detect bacteria concentrations less than CFU/mL. The plate culture method detected bacterial growth concentrations up to CFU/mL, but only 1 specimen of S. aureus was detected at the lowest concentration of CFU/mL. The broth culture method detected CFU/mL concentrations except for samples from S. aureus and E. coli strains. Among the CFU/mL lowest concentrations, bacterial growth detected 3 samples from S. aureus and 2 samples from E. coli. For the broth culture method, detection of bacterial growth up to CFU/mL took 58.9 hours, it took 57.5 hours for S. aureus and E. coli respectively, and it took 43.9 hours and 49.0 hours for CFU/mL concentrations of S. aureus and E. coli, respectively. The PCR method showed all positive results except for 1 specimen of E. coli. Conclusion: The broth culture method showed similar sensitivity to PCR except for the 43.9∼58.9 hours of an incubation period to show positive results. Overall, the PCR method was most sensitive and rapid method for detecting bacterial contamination in platelet concentrates.