BACKGROUND AND OBJECTIVES: Approximately 1 in every 2000 units of platelets is contaminated with bacteria. The BacT/ALERT automated blood culture system can be used to screen platelet concentrates (PCs) for bacterial contamination. MATERIALS AND METHODS: Data were collected from May 1998 until May 2004. The number of PCs tested during this period was 36 896, most of which were produced from pools of four buffy-coats. On the day following blood collection or platelet apheresis, a 5-10 ml sample of the PC was aseptically transferred to a BacT/ALERT culture bottle for detection of aerobic bacteria. The sample was monitored for bacterial growth during the entire storage period of the PC (6.5 days). When a positive signal was generated, the culture bottle, the PC and the erythrocyte concentrates were tested for bacterial growth. In order to determine the frequency of false-negative BacT/ALERT signals, 1061 outdated PCs were tested during the period from May 2002 to May 2004. RESULTS: Eighty-eight positive signals were detected by the BacT/ALERT system, of which 12 were interpreted as truly positive. Fourteen signals were interpreted as truly false positive. Thirty-three signals were interpreted to be probably false positive. Two of 1061 outdated units tested positive, and Bacillus spp. and Staphylococcus epidermidis, respectively, were isolated from these PCs. CONCLUSIONS: Between 0.03% and 0.12% of the PCs were contaminated with bacteria. BacT/ALERT is an efficient tool for monitoring PCs for bacterial contamination; however, it is important to realize that false-negative results may occur.
BACKGROUND AND OBJECTIVES: Approximately 1 in every 2000 units of platelets is contaminated with bacteria. The BacT/ALERT automated blood culture system can be used to screen platelet concentrates (PCs) for bacterial contamination. MATERIALS AND METHODS: Data were collected from May 1998 until May 2004. The number of PCs tested during this period was 36 896, most of which were produced from pools of four buffy-coats. On the day following blood collection or platelet apheresis, a 5-10 ml sample of the PC was aseptically transferred to a BacT/ALERT culture bottle for detection of aerobic bacteria. The sample was monitored for bacterial growth during the entire storage period of the PC (6.5 days). When a positive signal was generated, the culture bottle, the PC and the erythrocyte concentrates were tested for bacterial growth. In order to determine the frequency of false-negative BacT/ALERT signals, 1061 outdated PCs were tested during the period from May 2002 to May 2004. RESULTS: Eighty-eight positive signals were detected by the BacT/ALERT system, of which 12 were interpreted as truly positive. Fourteen signals were interpreted as truly false positive. Thirty-three signals were interpreted to be probably false positive. Two of 1061 outdated units tested positive, and Bacillus spp. and Staphylococcus epidermidis, respectively, were isolated from these PCs. CONCLUSIONS: Between 0.03% and 0.12% of the PCs were contaminated with bacteria. BacT/ALERT is an efficient tool for monitoring PCs for bacterial contamination; however, it is important to realize that false-negative results may occur.
Authors: Gabriele Walther-Wenke; Walter Däubener; Margarethe Heiden; Jochen Hoch; Britt Hornei; Peter Volkers; Carl Heinz Wirsing von König Journal: Transfus Med Hemother Date: 2011-07-11 Impact factor: 3.747
Authors: Anna Maria Leo; Maria Monica Salvadego; Maria Grazia Piva; Graziano Ruffato; Sara Valverde; Ernesto Trabuio; Francesco Antico; Gianluca Gessoni Journal: Blood Transfus Date: 2007-07 Impact factor: 3.443