Prevention - Bacterial Sepsis

Strategies for preventing bacterial sepsis vary according to potential cause. They are described in further detail below and include:

• Blood Donor Screening
• Blood Collection
• Component Storage and Transportation
• Visual Inspection of components
• Thawing and Pooling Blood Components
• Further possibilities.
• See Further Reading for more details about existing and proposed strategies being investigated

Blood Donor Screening

Strategies include deferral of potential donors for the following conditions:

• elevated temperature
• recent dental work
• not feeling well
• cold, flu, infection, or sore throat
• on antibiotics.

Blood Collection

Most bacteria found in platelets are normal skin flora, emphasizing the importance of aseptic blood collection techniques with careful skin sterilization.

Despite precautions, it may be almost impossible to decontaminate human skin. As well, needle coring may result in a small core of patient skin entering the needle at the time of blood collection and viable bacteria may be associated with deeper layers of skin, despite adequate surface disinfection. CBS has recently introduced whole blood collection bags with a sample diversion pouch for removal of an initial aliquot of 30-40 mL of donor blood. This approach reduces, but does not entirely eliminate, the rate of contamination by skin flora. However it does not decrease the rate of bacterial contamination due to other potentially more serious causes, in particular asymptomatic donor bacteremia.

Blood Component Storage and Transportation

Proper pretransfusion storage and transportation are critical to preventing bacterial growth in blood components that may be contaminated.

Policies must be in place to monitor and document the temperature of blood components, blood product storage equipment (e.g., refrigerators, freezers, platelet incubators), and transportation containers and take corrective action when necessary.

Visual Inspection

All blood components should be visually inspected upon labelling and entry into blood centre inventory, issue from the blood center, and prior to release for transfusion from the transfusion service. See an example of visual inspection criteria suitable for use in a transfusion service.

Individual hospital transfusion services may employ slightly different criteria as authorized by the medical director of the transfusion service.

Thawing & Pooling Blood Components

Several criteria relate to preventing bacterial contamination when transfusing, pooling, and thawing components. For example:

• When platelets are pooled immediately prior to transfusion, the product must be issued for transfusion within four hours.
• If RBC units are opened they must be transfused within 24 hours with appropriate storage in a controlled refrigerator until transfusion.
• Once transfusion is begun, a blood component should be transfused within four hours.
• Water baths used to thaw plasma and cryoprecipitate should be emptied and disinfected regularly. Donor units can be further protected from possible contamination by thawing components in plastic over-wraps.

NOTE: Frozen products must be thawed in the transfusion service according to standard operating procedures and specialized equipment and must NOT be thawed on hospital wards, unless the procedure is properly controlled and plasma thawing equipment is used.

Further Possibilities

Research on further ways to reduce transfusion-related transmission of bacteria and other organisms includes bacterial detection systems and pathogen inactivation.

Several methods for bacterial detection have been investigated, including visual inspection, culture, Gram's staining or acridine orange staining, PCR, chemiluminescence-linked rRNA hybridization, and urine reagent strips (to measure pH and glucose consumption). The American Association of Blood Banks (AABB) has recently published an Association Bulletin advising its membership on the use of those techniques. (See further reading)

Several pathogen inactivation methods are under investigation. These methods involve the exposure of blood components to reagents such as psoralen, riboflavin, dimethylmethylene blue and inactine in order to inactivate a variety of pathogens including viruses, bacteria, protozoa and fungi.