Modulation of biofilm formation, virulence, and antimicrobial resistance by Staphylococcus aureus during platelet storage

Bacterial contamination of platelets is currently the major microbiological cause of post-transfusion severe reactions. Bacteria are introduced into the donated blood during venipuncture and can be present in all blood components manufactured from whole blood. However, within all transfusable blood components, platelet concentrates are the most susceptible to bacterial contamination due to their storage conditions under agitation for up to 7 days in gas-permeable plastic containers, at room temperature. Normal skin flora bacteria are the predominant platelet contaminants although bacteria that normally reside in the mucosa of the nostrils can also be found in the skin and contaminate the collected blood. An example of such bacteria is the pathogen Staphylococcus aureus. This organism is one of the major causes of hospital-acquired infectious and famously known for its antibiotic resistance (super bug). Despite all the strategies implemented to mitigate the risk of transfusing bacterially-contaminated platelets, Staphylococcus aureus has the tendency to escape detection and cause septic transfusion reactions as recently reported in Canada, the US, and the UK. Missed detection of Staphylococcus aureus during platelet screening with culture methods is attributed to slow growth and formation of aggregates that adhere to platelets and the platelet storage bag. In addition to antibiotic resistance, Staphylococcus aureus produces toxins that can be very harmful to platelet recipients. The present proposal aims to investigate the conditions that favor Staphylococcus aureus growth and toxin production in platelets, the factors contributing to missed detection, and the safety implications of these changes for transfusion patients.

RAMIREZ-ARCOS, Sandra

Canadian Blood Services

Intramural Research Grant Program

Ontario

$323,253