Detection of Bacterial Contamination in Platelet Concentrates Using Flow Cytometry and Real-Time PCR Methods

Abstract

Despite considerable advances in the safety of blood components based on the application of highly sensitive and specific screening methods to minimize the viral infection risk, the prevention of transfusion-associated bacterial infection remains a major challenge in transfusion medicine. In particular, platelet concentrates represent the greatest infectious risk of transfusion-transmitted bacterial sepsis. The detection of bacterial contamination in platelet concentrates has been implemented in several blood services as a routine quality control testing. Although culture is likely to remain the gold standard method of detecting bacterial contamination, the use of rapid methods is likely to increase and play an important role in transfusion medicine in the future. In particular, flow cytometric methods and nucleic acid amplification techniques are powerful tools in bacterial screening assays. Compared to culture-based methods, the combination of high sensitivity and specificity, low contamination risk, ease of performance, and speed has made those technologies appealing alternatives to conventional culture-based testing methods.

Enlargement of the WHO international repository for platelet transfusion‐relevant bacteria reference strains

“…According to the published literature, experience is most extensive with the BacT/ALERT automated culture system (Biomerieux Inc, Marcy‐l’Étoile, France) and substantial reductions in septic transfusion reactions have been documented . Routine‐use and clinical outcome studies of rapid bacterial detection systems performed on the day of transfusion have been published, including studies using lateral flow immunoassays , colorimetric assays , flow cytometry and PCR . PR systems offer an alternative to microbiological detection methods and haemovigilance data support their effectiveness .…”

“…Culture sensitivity can be improved by delayed product sampling and larger sample volumes [9][10][11] to enable detection in spite of low bacterial loads (<1 CFU/ml) at the time of sampling. For rapid bacterial detection methods (point of issue tests) [12][13][14][15][16][17][18], the analytical sensitivity of the assays requires high cell counts of bacteria (10 2 -10 5 CFU/ml) for detection. They are best performed as close as possible to the time of transfusion.…”

Residual risk of bacterial contamination of platelets: six years of experience with sterility testing

“…Several testing systems are currently in use worldwide to interdict bacterially contaminated PCs before transfusion. Although bacterial culture systems are broadly used by blood operators for early PC screening, the application of point‐of‐issue tests, including polymerase chain reaction, flow cytometry, immunoassays, and colorimetric assays, varies, because these assays are generally used close to the time of transfusion …”

“…Although bacterial culture systems are broadly used by blood operators for early PC screening, 4,5 the application of point-of-issue tests, including polymerase chain reaction, flow cytometry, immunoassays, and colorimetric assays, varies, because these assays are generally used close to the time of transfusion. [7][8][9] Canadian Blood Services implemented PC screening with the automated BacT/ALERT 3D culture system (bio-M erieux) in 2004. 10 Currently, 100% of the leukocytereduced PC products, approximately 30% of which are apheresis PCs and approximately 70% of which are buffy coat pooled PCs, are screened within 24 to 30 hours of phlebotomy.…”

Emerging Pathogens - How Safe is Blood?

“…Nevertheless, shelf-life reduction was not able to prevent every case of serious bacterial transmission. In addition, due to new screening strategies with rapid bacterial detection methods, like Bactiflow [9,10] and 16S and 23S rDNA NAT [11,12,13], the introduction of pathogen reduction methods [14,15,16,17,18] is a promising option to cover the bacterial contamination risk in the near future.…”