A suspected septic transfusion reaction associated with posttransfusion contamination of a platelet pool by vancomycin‐resistant Enterococcus faecium

Abstract

BACKGROUND: Vancomycin-resistant enterococci (VRE) are antibiotic-resistant organisms associated with both colonization and serious life-threatening infection in health care settings. Contamination of platelet concentrates (PCs) with Enterococcus can result in transfusion-transmitted infection.CASE PRESENTATION: This report describes the investigation of a septic transfusion case involving a 27-year-old male patient with relapsed acute leukemia who was transfused with a 5-day-old buffy coat PC pool and developed fever and rigors.DISCUSSION: Microbiology testing and pulse-field gel electrophoresis (PFGE) was done on patient blood cultures obtained from peripheral and central lines. Microbiology and molecular testing were also performed on the remaining posttransfusion PC pool, which was refrigerated for 24 hours before microbiology testing. Red blood cell (RBC) and plasma units associated with the implicated PCs were screened for microbial contamination. Patient blood cultures obtained from peripheral and central lines yielded vancomycin-resistant Enterococcus faecium. Gram stain of a sample from the platelet pool was negative but coagulase-negative Staphylococcus (CNST) and VRE were isolated on culture. Antibiotic sensitivity and PFGE profiles of several VRE isolates from the patient before and after transfusion, and the PC pool, revealed that all were closely related. Associated RBC and plasma components tested negative for microbial contamination. CONCLUSIONS: Microbiological and molecularinvestigations showed a relationship between VRE isolated from the patient before and after transfusion, and therefore it is postulated that a patient-to-PC retrograde contamination (from either blood or skin) occurred. As the CNST isolated from the PC pool was not isolated from patient samples, its implication in the transfusion event is unknown. V ancomycin-resistant enterococci (VRE), which comprise the species Enterococcus faecium and Enterococcus faecalis, are health care-associated antibiotic-resistant organisms implicated in both serious life-threatening infection and human colonization and environmental contamination. 1-3 Patients with VRE bacteremia are at greater risk for longer hospital stay and mortality than patients with bacteremia caused by vancomycin-susceptible enterococci. 4 Patients at highest risk for VRE bacteremia include those admitted to an ABBREVIATIONS: CNST = coagulase-negative Staphylococcus; ICU = intensive care unit; PCs = platelet concentrates; PFGE = pulse-field gel electrophoresis; RSV = respiratory syncytial virus; VRE = vancomycin-resistant enterococci. From the

Limitations of current practices in detection of bacterially contaminated blood products associated with suspected septic transfusion reactions

“…In the last of these three, the patient was septic with E . faecalis prior to transfusion and the positive component result was thought to be due to possible backwash into the component 16 . No plasma components were associated with an imputability of “definite.”…”

“…However, these same organisms may represent clinically insignificant “secondary contamination” that can occur during post‐transfusion component discard, retrieval for culture, or manipulation of the bag at the time of sampling for culture. Further complicating the interpretation of primary versus secondary contamination is a recent report of retrograde travel of bacteria from the patient into the component 16 …”

Bacterial Contamination of Platelet Products

“…A recent report on the source of polymicrobial contamination of apheresis units resulting in transfusion-transmitted sepsis contaminated with Acinetobacter calcoaceticus-baumannii complex, Staphylococcus saprophyticus and Leclercia adecarboxylata found evidence that the manufacturer of the platelet collection kits used was the most probable source of this contamination [ 14 ]. Retrograde contamination of a platelet unit can also occur in patients with bacteremia at the time of receiving a platelet transfusion as documented by a case where Enterococcus faecium was isolated from a patient’s blood cultures before and after transfusion, with the same species recovered from the platelet unit remnants after transfusion [ 15 ].…”

“…A recent report on the source of polymicrobial contamination of apheresis units resulting in transfusion-transmitted sepsis contaminated with Acinetobacter calcoaceticus-baumannii complex, Staphylococcus saprophyticus and Leclercia adecarboxylata found evidence that the manufacturer of the platelet collection kits used was the most probable source of this contamination [14]. Retrograde contamination of a platelet unit can also occur in patients with bacteremia at the time of receiving a platelet transfusion as documented by a case where Enterococcus faecium was isolated from a patient's blood cultures before and after transfusion, with the same species recovered from the platelet unit remnants after transfusion [15]. Investigation of the sources of Staphylococcus aureus contaminating 16 platelet products, 13 apheresis collections and 3 buffy coat pools, in England documented that a strain identical or closely related to each platelet isolate was cultured from the skin or nares of 12 of the 13 apheresis donors and one of the donors in each of the 3 pools [16].…”