02676nas a2200193   4500008004100000020001400041024001700055245016200072210006900234260020500303300001300508490000700521520182100528100001702349700002002366700002102386700002602407856004902433       2015                        eng d  a1537-2995  awdn, 041736000aFatal false-negative transfusion infection involving a buffy coat platelet pool contaminated with biofilm-positive Staphylococcus epidermidis: a case report.0 aFatal falsenegative transfusion infection involving a buffy coat  aUnited StatesbKou,Yuntong. Canadian Blood Services.Pagotto,Franco. Health Canada, Ottawa, Ontario, Canada.Hannach,Barbara. Canadian Blood Services.Ramirez-Arcos,Sandra. Canadian Blood Services.c2015  a2384 - 90 v553 aBACKGROUND: Bacterial contamination of platelet concentrates (PCs) poses the major posttransfusion infectious risk in developed countries. The aerobic microorganism most frequently isolated from PCs is coagulase-negative Staphylococcus epidermidis, a normal inhabitant of the human skin, which has been involved in fatal transfusion reactions worldwide., CASE REPORT: In September 2014, a splenectomized elderly male patient, suffering from leukemia, was transfused with two 5-day-old buffy coat platelet (PLT) pools. The patient returned to emergency on the same day with a low-grade fever. He was bacteremic and died on the next day. Microbiology and molecular testing of a blood sample from the patient and one of the PCs yielded the same S. epidermidis strain. Further analysis demonstrated that this S. epidermidis isolate displays a biofilm-positive phenotype in PCs., DISCUSSION: At Canadian Blood Services, PCs are screened for bacterial contamination with the BacT/ALERT system (bioMerieux) at approximately 24 hours postcollection. The implicated PC had been tested and yielded a false-negative culture result. A titration experiment indicated that, at the time of screening, the contaminated PC had a titer of less than 0.74 colony-forming units (CFU)/mL (<227 CFUs/unit) of S. epidermidis. Mathematical models have predicted that up to 70% of PCs contaminated with coagulase-negative staphylococci at concentrations of 0.02 CFU/mL can be missed by BacT/ALERT screening., CONCLUSION: Despite several mitigation strategies, false-negative cultures with current PLT screening practices still occur. This report creates awareness of the pathogenicity of opportunistic S. epidermidis, a low-virulence organism, in susceptible patients who may not develop a typical transfusion reaction.Copyright © 2015 AABB.1 aKou, Yuntong1 aPagotto, Franco1 aHannach, Barbara1 aRamirez-Arcos, Sandra  uhttps://www.notifylibrary.org/reference/4444