Single or multiple RT exposures did not affect RBC quality but slightly promoted bacterial growth in contaminated units. The clinical significance of these results remains unclear and needs further investigation.

The bulk of coagulation factor activity losses during storage occurred in the first 24 hours. Coagulation factor activities remaining in FP after 5 days did not differ from those previously reported in similar products frozen within 24 hours of phlebotomy. While DEHP levels in 5-day-thawed FP are not of concern for adult patients, for infants, DEHP levels can be minimized by using FP refrigerated for no more than 24 hours.

This study demonstrates the capability of the BacT/ALERT3D system to detect aerobic and anaerobic bacterial contamination in all tested blood components, thereby supporting its use for quality control sterility testing and not only bacterial screening. A standardized process will allow CBS to evaluate and compare blood collection and manufacturing practices across the country.

Testing of outdated BCPs suggests that introducing anaerobic cultures would result in significant PLT wastage due to a high rate of false positives. Contaminated BCPs still escape detection during initial testing; therefore, extension of PLT storage may be possible if repeat screening is performed before transfusion.

There is no added risk to RBC safety by increasing RT exposures to 60 min with each removal from storage for up to a total of 3 h during RBC shelf life. Therefore, extending the 30-min limitation in RBCs exposed to uncontrolled temperatures to 60 min should be considered by regulatory agencies.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet (PLT) preparations and have been implicated in adverse transfusion reactions worldwide. The most frequently identified contaminant is Staphylococcus epidermidis, which is noted for its ability to maintain chronic hospital-acquired infections by forming biofilms as a chief virulence mechanism. STUDY DESIGN AND METHODS: Strains of S. epidermidis isolated from contaminated PLT preparations in Canada were distinguished via gene-specific polymerase chain reaction (PCR) with divIVA as a marker. Biofilm-forming ability was assessed by the presence of the gene icaD, slime production on Congo red agar, and biofilm formation on polystyrene surfaces. Production of polysaccharide intercellular adhesin (PIA) was resolved by immunofluorescence. RESULTS: Eight of the 13 (62%) CoNS isolates under study were identified as S. epidermidis. Of these, four strains (50%) were classified as strong biofilm producers. Three of the four biofilm-positive strains (75%) produced slime, harbored the icaD gene, and had positive expression of PIA. CONCLUSIONS: Despite the presumable commensal origin of the CoNS isolates, a large proportion of S. epidermidis strains demonstrated a potential for enhanced virulence. Identification of contaminant staphylococci as biofilm producers is thus relevant and informative with regard to treatment approach in the circumstance of inadvertent infection of a PLT recipient. ABBREVIATIONS: ATCC = American Type Culture Collection; ATR(s) = adverse transfusion reaction(s); CoNS = coagulasenegative staphylococci; PIA = polysaccharide intercellular adhesin; TSB(g) = trypticase soy broth (+0.5% glucose). TRANSFUSION 2008;48:969-977. Volume 48, May 2008 TRANSFUSION 969 * Percent confidence of species identification from initial test with the API Staph database (bioMérieux, Marcy L'Etoile, France). † Reidentified as S. epidermidis based on the presence of divIVA and ribotyping analysis. BC = whole blood-derived PLTs prepared by the buffy-coat method; Aph = single-donor apheresis PLTs; PRP = whole blood-derived PLTs prepared by the PLT-rich plasma method; ND = not determined. GRECO ET AL. 970 TRANSFUSION Volume 48, May 2008 Fig. 4. Production of PIA by PLT contaminant isolates. Indirect immunofluorescence was performed with primary antibody a-PIA and FITC-conjugated secondary antibody. S. epidermidis ATCC 35984 (A, B) and ATCC 12228 (C, D) were included as biofilm-positive and biofilm-negative controls, respectively. Contaminant strains that were positive for PIA production are

This study shows that the current sterility testing process at the Canadian Blood Services Stem Cell Laboratory detected the tested aerobic but not the anaerobic microbial contaminants in HSCs. The ability of the BacT/ALERT system using BPA and BPN bottles to detect bacterial contamination in HSCs was also demonstrated.

Despite the presumable commensal origin of the CoNS isolates, a large proportion of S. epidermidis strains demonstrated a potential for enhanced virulence. Identification of contaminant staphylococci as biofilm producers is thus relevant and informative with regard to treatment approach in the circumstance of inadvertent infection of a PLT recipient.