Bacterial Contamination of Blood Components: Risks, Strategies, and Regulation

Abstract

Bacterial contamination of transfusion products, especially platelets, is a longstanding problem that has been partially controlled through modern phlebotomy practices, refrigeration of red cells, freezing of plasma and improved materials for transfusion product collection and storage. Bacterial contamination of platelet products has been acknowledged as the most frequent infectious risk from transfusion occurring in approximately 1 of 2,000-3,000 whole-blood derived, random donor platelets, and apheresis-derived, single donor platelets. In the US, bacterial contamination is considered the second most common cause of death overall from transfusion (after clerical errors) with mortality rates ranging from 1:20,000 to 1:85,000 donor exposures. Estimates of severe morbidity and mortality range from 100 to 150 transfused individuals each year.Concern This Joint ASH and AABB Educational Session reviews the risks, testing strategies, and regulatory approaches regarding bacterial contamination of blood components to aid in preparing practitioners of hematology and transfusion medicine in understanding the background and clinical relevance of this clinically important issue and in considering the approaches currently available for its mitigation, as well as their implementation.In this chapter, Drs. Hillyer and Josephson review the background and significance of bacterial contamination, as well as address the definitions, conceptions and limitations of the terms risk, safe and safety. They then describe current transfusion risks including non-infectious serious hazards of transfusion, and current and emerging viral risks. In the body of the text, Dr. Blajchman reviews the prevalence of bacterial contamination in cellular blood components in detail with current references to a variety of important studies. He then describes the signs and symptoms of transfusion-associated sepsis and the sources of the bacterial contamination for cellular blood products including donor bacteremia, and contamination during whole blood collection and of the collection pack. This is followed by strategies to decrease the transfusion-associated morbidity/mortality risk of contaminated cellular blood products 576American Society of Hematology including improving donor skin disinfection, removal of first aliquot of donor blood, pretransfusion detection of bacteria, reducing recipient exposure, and pathogen reduction/inactivation. In the final sections, Drs. Vostal, Epstein and Goodman describe the regulations and regulatory approaches critical to the appropriate implementation of a bacterial contamination screening and limitation program including their and/or the FDA's input on prevention of bacterial contamination, bacterial proliferation, and detection of bacteria in transfusion products. This is followed by a discussion of sampling strategy for detection of bacteria in a transfusion product, as well as the current approval process for bacterial detection devices, trials recommended under "actual clinical use" conditions, pathogen reduction ...

Screening of platelet concentrates for bacterial contamination: spectrum of bacteria detected, proportionof transfused units, and clinical follow-up

“…Bacterial contamination of blood products is mostly due to contamination by skin bacteria that gain access to the unit of blood collection [25]. Migration of bacteria on the skin at the insertion site into the cutaneous catheter tract with colonization of the catheter tip is the most common route of catheter-related infections [26].…”

Platelets: Testing, Dosing and the Storage Lesion—Recent Advances

“…4 Clinically apparent septic transfusion reactions were thought to occur following ~1/25,000 platelet transfusions, although there is considerable uncertainty around this point estimate. 4 All AABB accredited blood banks were required to meet standard 5.1.5.1 by March 1, 2004. How this standard is being met varies by facility.…”

“…12,13 The prevalence of septic reactions was dramatically lower in the BaCon study than in the other two studies; it has been argued that the BaCon study was limited by an underestimation bias. 4 A large post-standard 5.1.5.1 study is also summarized in Table 1. 15 Over a 10-month period, apheresis platelets collected at 36 American Red Cross blood centers were cultured 24 hours after collection using the BacT/ALERT system.…”

Transfusion-transmissible infections and transfusion-related immunomodulation

“…In the past the safety of blood transfusions could be enhanced through modern phlebotomy practices (arm cleansing using an iodine / alcohol mix, and diverting the first 50ml of each blood donation), refrigeration of red cells, freezing of plasma and improved materials for transfusion product collection and storage [25]. However, concentrates is contaminated and 1 in every 25'000 platelet concentrates has been reported to cause sepsis [26].…”