Fatal group C streptococcal infection due to transfusion of a bacterially contaminated pooled platelet unit despite routine bacterial culture screening.
BACKGROUND
An elderly man with chronic myelomonocytic leukemia developed respiratory distress and died less than 48 hours after transfusion of a pool of eight whole blood-derived platelets (PLTs). Blood cultures from the recipient and cultures of remnants from the pooled PLT bag grew group C streptococci (GCS). An investigation was conducted to identify both the infection's source and the reasons for the false-negative screening result.


METHODS
Red blood cell (RBC) units (cocomponent from the eight donations) were traced, quarantined, and cultured. Specimens from the implicated donor were obtained. Isolates were identified and typed by 16S rRNA and pulsed-field gel electrophoresis (PFGE). The blood center screening method was reviewed.


RESULTS
beta-Hemolytic GCS, cultured from 1 of 8 RBC units, linked the fatal case to a single donor. The donor's throat swab collected 20 days after donation was positive for the presence of GCS, identified as Streptococcus dysgalactiae subsp. equisimilis. Isolates from the recipient, RBC unit, residual PLTs, and donor's throat swab were indistinguishable by PFGE. The donor denied any symptoms of infection before or after donation. PLT bacterial screening at the blood center was performed using a commercially available bacterial detection system (BacT/ALERT, bioMérieux) with a threshold of 15 colony-forming units per bag.


CONCLUSIONS
An asymptomatic donor was implicated as the source of GCS-contaminated PLTs. Current screening methods for PLTs are not sufficient to detect all bacterial contamination. Pooled PLTs are a particular challenge because the small volume of individual units places limits on culturing strategies. Improved detection of bacterial contamination of PLTs is needed.
Office of Workforce and Career Development, Division of Healthcare Quality Promotion, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. flessa@cdc.gov
Fernanda
F
Lessa
German F
GF
Leparc
Kaaron
K
Benson
Roger
R
Sanderson
Chris A
CA
Van Beneden
Patricia L
PL
Shewmaker
Bette
B
Jensen
Matthew J
MJ
Arduino
Matthew J
MJ
Kuehnert
D000368:Aged; D001782:Blood Donors; D001792:Blood Platelets / Q000382:microbiology*; D017809:Fatal Outcome; D006801:Humans; D008297:Male; D008828:Microbiological Techniques; D017713:Platelet Transfusion / Q000009:adverse effects*; D013290:Streptococcal Infections / Q000635:transmission*; D013291:Streptococcus / Q000145:classification / Q000302:isolation & purification*