Bench Test for the Detection of Bacterial Contamination in Platelet Concentrates Using Rapid and Cultural Detection Methods with a Standardized Proficiency Panel

Abstract

Background: The most frequent infectious complication in transfusion therapy in developed countries is related to the bacterial contamination of platelet concentrates (PCs). Rapid and cultural screening methods for bacterial detection in platelets are available, but external performance evaluation, especially of rapid methods, has been difficult to realize so far. Here we summarize the results of three individual collaborative trials using an external quality assessment program (EQAP) for the application of current rapid and cultural screening methods. Methods: Three different modules were available for the detection of bacterial contamination: module 1: rapid methods, module 2: culture methods, module 3: bacterial identification methods. The sample set-up included up to six different bacterial strains, 1-2 negative samples and 4-6 positive samples with stabilized bacterial cell counts (approximately 10³/10⁴/10⁵ CFU/ml). Time schedule for testing was limited (module 1: 6 h, module 2 and 3: 7 days). Results: Samples of module 1 were analyzed with two different rapid methods (BactiFlow, NAT). The results of the three individual collaborative trials showed that all participants detected the negative samples with both assays correctly. Samples spiked with 10⁴ to 10⁵ CFU/ml of bacteria obtained positive results with both rapid screening methods, whereas samples spiked with only 10³ CFU/ml disclosed a lower number of correctly identified positive results by NAT (86.6-93.8% sensitivity) compared to BactiFlow (100% sensitivity). The results for modules 2 and 3 revealed a 100% diagnostic sensitivity and specificity in all three collaborative trials. Conclusion: This proficiency panel facilitates the verification of the analytical sensitivity of rapid and cultural bacterial detection systems under controlled routine conditions. The concept of samples provided in this EQAP has three main advantages: i) samples can be examined by both rapid and culture methods, ii) the provided material is matrix-equivalent, and iii) the sample material is ready-to-use.

Late sampling for automated culture to extend the platelet shelf life to 5 days in Germany

“…Apheresis‐derived single‐donor PCs were prepared as described previously . All donors provided informed consent that PCs may be used for research purposes.…”

“…Apheresis-derived single-donor PCs were prepared as described previously. 26 All donors provided informed consent that PCs may be used for research purposes. The final product consisted of 2.0 to 4.0 3 10E 1 11 platelets/U (205-295 mL) and 0.16 to 0.24 L/L ACD-A stabilizer and 0.76 to 0.84 L/L plasma/mL preparation.…”

Establishment of a proficiency panel for an external quality assessment programme for the detection of bacterial contamination in platelet concentrates using rapid and cultural detection methods

“…The design of the proficiency panel samples described in this study demonstrated to be an effective tool to examine the performance of both, rapid and cultural detection methods in the same setting with ready‐to‐use sample material. The handling and applicability of sample material was further demonstrated by a pilot EQAP; in the meantime, additional EQAPs were conducted, also confirming these initial results . The innovative design of this EQAP concept permits the microbiological control of PCs under routine conditions, in contrast to other currently available EQAPs which fail to fulfil the real environmental conditions of bacterial screening with rapid detection methods.…”

“…Apheresis‐derived single‐donor PCs (APCs) and pooled PCs (PPCs) were prepared as described previously . All donors provided informed consent that platelets may be used for research purposes.…”

Implications of the US Food and Drug Administration draft guidance for mitigating septic reactions from platelet transfusions

“…These include the BactiFlow flow cytometric assay or nucleic acid test. 25 BactiFlow has a limit of detection of 150 CFU/mL with ,1 hour result time. 26 Use of the BactiFlow detected 12 additional true positives (12/34 631; 1/2886) and 12 false positive (false positive rate of 0.03%).…”