Cherie Mastronardi

Assessment of biofilm‐forming ability of coagulase‐negative staphylococci isolated from contaminated platelet preparations in Canada

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.

Changes in coagulation factor activity and content of di(2-ethylhexyl)phthalate in frozen plasma units during refrigerated storage for up to five days after thawing.

BACKGROUND: Thawed plasma is typically transfused to supply coagulation factors but factor activity declines during refrigerated storage. Refrigerating thawed plasma for longer than 24 hours could reduce plasma wastage and make plasma more readily available for emergency transfusions. We measured coagulation factor activity and di(2‐ethylhexyl)phthalate (DEHP) concentration in frozen plasma (FP) thawed and stored at 1 to 6°C for up to 5 days.

Evaluation of the BacT/ALERT 3D system for the implementation of in-house quality control sterility testing at Canadian Blood Services.

Abstract Background: Until recently, Canadian Blood Services (CBS) was performing quality control sterility testing of blood components using three different processes. This study was conducted in order to standardize sterility testing at all CBS centers in a cost-effective manner using the BacT/ALERT® 3D system. Methods: Blood components including fresh frozen plasma, platelet concentrates, and red blood cells were inoculated with eight bacterial species at target concentrations of 1 and 10 CFU/mL. Pre- and post-spiked samples were inoculated into BacT/ALERT® aerobic and anaerobic culture bottles and incubated for a maximum of 10 days. Specificity of the positive culture bottles was verified by Gram staining. Positive results obtained pre- and post-implementation of the in-house sterility testing program at CBS were collected and analyzed. Results: The BacT/ALERT®3D system detected all bacteria in all blood components tested in this validation. Positive cultures were obtained within 28 h of incubation with the exception of Propionibacterium acnes which was detected within 134 h. The percentage of positive cultures ranged from 0.01% to 0.2%. All contaminants isolated were either normal skin flora or environmental microorganisms. Conclusions: This study demonstrates the capability of the BacT/ALERT®3D 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. Clin Chem Lab Med 2010;48:1179–87.

Evaluating the 4‐hour and 30‐minute rules: effects of room temperature exposure on red blood cell quality and bacterial growth

BACKGROUND: A 30‐minute rule was established to limit red blood cell (RBC) exposure to uncontrolled temperatures during storage and transportation. Also, RBC units issued for transfusion should not remain at room temperature (RT) for more than 4 hours (4‐hour rule). This study was aimed at determining if single or multiple RT exposures affect RBC quality and/or promote bacterial growth.

Bacterial screening of outdated buffy coat platelet pools using a culture system and a rapid immunoassay

BACKGROUND: Canadian Blood Services performs bacterial screening of buffy coat platelet pools (BCPs) using aerobic BacT/ALERT cultures. This study aimed to determine the rate of detection failures during initial platelet (PLT) screening and evaluate the introduction of anaerobic cultures and immunoassay testing to assess the safety of extending PLT storage beyond 5 days.

Evaluation of the sterility testing process of hematopoietic stem cells at Canadian Blood Services

BACKGROUND: Sterility testing of hematopoietic stem cells (HSCs) at The Canadian Blood Services Stem Cell Laboratory is performed using BacT/ALERT aerobic (SA) culture bottles. This study was conducted to verify the efficacy of this method and to assess the use of the BacT/ALERT aerobic (BPA) and anaerobic (BPN) culture bottles for microbial testing of HSCs.

Bacterial growth in red blood cell units exposed to uncontrolled temperatures: challenging the 30-minute rule.

The ‘30‐min rule’ requires discarding red blood cells (RBCs) exposed to uncontrolled temperatures for >30 min to ensure safe RBC transfusion. This study was aimed at determining whether multiple room temperature (RT) exposures promote bacterial growth.

Process improvement by eliminating mixing of whole blood units after an overnight hold prior to component production using the buffy coat method.

The elimination of a thorough manual mixing of whole blood (WB) which takes place following the overnight hold, but before the first centrifugation step, during buffy coat component production at Canadian Blood Services (CBS) was investigated. WB was pooled after donation and split. Pairs of platelet, red blood cell (RBC), and plasma components were produced, with half using the standard method and half using a method in which the mixing step was eliminated. Quality assessments included yield, pH, CD62P expression and morphology for platelets, hemoglobin, hematocrit, hemolysis, and supernatant K+ for RBCs, and volume and factor VIII activity levels for plasma. All components, produced using either method, met CBS quality control criteria. There were no significant differences in platelet yield between components produced with and without mixing. A significant difference was seen for RBC hemolysis at expiry (P = 0.03), but for both groups, levels met quality control requirements. Noninferiority of components produced without mixing was confirmed for all parameters. Manual mixing is laborious and has a risk of repetitive strain for production staff and its significance is unclear. Elimination of this step will improve process efficiencies without compromising quality.

Implementation of a proficiency testing programme for bacterial screening in platelet preparations in Canada

Background and Objectives  Bacterial screening in apheresis platelet preparations was implemented in March of 2004 by Canadian Blood Services (CBS) using the BacT/ALERT® system. The aim of this study was to develop, validate and implement an in‐house proficiency testing programme to evaluate CBS performance of bacterial screening in platelet preparations.

Assessment of biofilm-forming ability of coagulase-negative staphylococci isolated from contaminated platelet preparations in Canada: BIOFILM FORMATION BY STAPHYLOCOCCI ISOLATED FROM PLTs

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.