Validation of a microbial detection system for use with ACD-A platelets with PAS III platelet additive solution

Area of Science:

• Microbiology
• Transfusion Medicine
• Clinical Diagnostics

Background:

• The BacT/ALERT microbial detection system (BTA) is utilized for testing leukoreduced apheresis platelets (LR-AP) in plasma.
• Platelet additive solutions (PASs), such as InterSol, are employed to minimize plasma transfusion in LR-AP.

Purpose of the Study:

• To evaluate the efficacy of the two-bottle BTA testing scheme for microorganism recovery from LR-AP in InterSol-plasma.
• To compare the BTA system's performance against a reference plate culture method.

Main Methods:

• Hyperconcentrated, double LR-AP were collected and mixed with InterSol (65% InterSol:35% plasma).
• Samples were inoculated with one of 10 index organisms at two levels and tested using aerobic (BPA) and anaerobic (BPN) BTA bottles (4 mL each).
• A reference method used blood agar plates (BAPs) for aerobic and anaerobic cultures (0.5 mL each).

Main Results:

• The BTA system demonstrated zero false-positives from 103 bottle pairs.
• All 400 two-bottle BTA tests were positive within 24 hours, with exceptions for Propionibacterium acnes and Streptococcus viridans.
• At bacterial concentrations of 40 colony-forming units (CFUs)/mL or less, BTA achieved 100% positivity, compared to 94% for BAP.

Conclusions:

• The two-bottle BTA system exhibited superior seeded organism recovery compared to the two-plate BAP system for InterSol platelets.
• The performance of the BTA system with InterSol platelets is comparable to previous findings with platelets in plasma.
• InterSol additive solution does not appear to negatively impact the performance of the two-bottle BTA detection system.