Evaluation of Mirasol pathogen reduction system by artificially contaminating platelet concentrates with Staphylococcus epidermidis: A pilot study from India.

BACKGROUND AND OBJECTIVES: This study was conducted to assess the efficacy of Mirasol pathogen reduction system for platelets aimed at preventing bacterial regrowth by spiking buffy coat pooled platelets (BCPP) with clinically relevant load of Staphylococous epidermidis.

MATERIALS AND METHODS: BCPP units were prepared using Teruflex BP-kit with Imugard III-S-PL (Terumo BCT, Tokyo, Japan). Two BCPP units were pooled, of which 40 ml of negative control (NC) was removed. The remaining volume of the platelet unit was inoculated with clinically relevant load of bacteria (total of 30 CFU of S. epidermidis in 1 ml); following this the platelet unit was split into two parts. One part served as positive control (PC) and the other part was subjected to pathogen reduction technique (Mirasol PRT, CaridianBCT Biotechnologies, Lakewood, CO, USA). Bacterial detection was performed using BacT/ALERT system, controls after day 1 and day 7 following inoculation of bacteria and on day 7 for Mirasol-treated unit.

RESULTS: Of the 32 treatment cycles, 28 were valid and 4 were invalid. No regrowth was observed in 96.4% (27 of 28) after treatment with Mirasol pathogen reduction system. Of four invalid tests, on two instances the NC showed growth, whereas in other 2 no regrowth was detected in 7(th) day PC. Bacterial screening of PCs by BacT/ALERT after 24 h of incubation was 28.6%, whereas the effectiveness increased to 100% when incubated for 7 days.

CONCLUSIONS: Mirasol system was effective in inactivating S. epidermidis when it was deliberately inoculated into BCPP at clinically relevant concentrations. Such systems may significantly improve blood safety by inactivating traditional and emerging transfusion-transmitted pathogens.