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

Lee, Hyukmin; Park, Younhee; Lim, Hwan Sub

Abstract

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 22~24degrees C, 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 (10(1)~10(5) 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 10(4) CFU/mL. The plate culture method detected bacterial growth concentrations up to 10(3) CFU/mL, but only 1 specimen of S. aureus was detected at the lowest concentration of 10(1) CFU/mL. The broth culture method detected 10(2) CFU/mL concentrations except for samples from S. aureus and E. coli strains. Among the 10(1) 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 10(1) 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 10(2) 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.