Common Causative Organisms of Blood Transfusion Infections
Bacterial contamination of blood products, most frequently platelets, is the leading cause of death from blood transfusions, while viral infections including hepatitis B, hepatitis C, and HIV remain important but now rare risks due to modern screening. 1
Bacterial Infections: The Leading Cause of Transfusion-Related Deaths
Bacterial contamination represents the most common infectious cause of transfusion-related mortality. 1 This occurs most frequently with platelet products due to their storage temperature of 20-24°C, which promotes bacterial overgrowth. 1
Key Clinical Features:
- Fever developing within 6 hours after receiving platelets suggests possible sepsis from contaminated products 1
- Many blood banks now culture platelet concentrates routinely to detect contamination 1
- Coagulase-negative staphylococci are the most common bacterial pathogens, accounting for 37% of hospital-acquired bloodstream infections 1
- Staphylococcus aureus accounts for 12.6% of transfusion-related bloodstream infections, with >50% now resistant to oxacillin 1
- Enterococci represent 13.5% of cases, with 25.9% resistant to vancomycin 1
Viral Infections: Now Rare But Still Relevant
Hepatitis Viruses
Hepatitis C virus (HCV) was historically the most common viral infection transmitted by transfusion, with prevalence rates in thalassemia patients ranging from 4.4% to 85.4% before modern screening. 1 The current risk of HCV transmission is estimated at less than 2.5 per 1 million donations in developed countries. 1
Hepatitis B virus (HBV) transmission risk has been reduced to approximately 0.002% per transfusion recipient through HBsAg screening and nucleic acid technology. 1 The prevalence in multiply-transfused patients ranges from 0.3% to 5.7%. 1
Hepatitis E virus (HEV) has emerged as an important transfusion-transmitted pathogen, with viraemic donor frequencies ranging from 1:600 in the Netherlands to 1:74,131 in Australia. 1 Transfusion-transmitted HEV infection occurs in approximately 42-50% of recipients receiving infected blood components with sufficient viral load. 1
Retroviruses
Human immunodeficiency virus (HIV) transmission risk is now extremely low due to nucleic acid technology screening, though it remains a concern during the window period. 1, 2
Human T-cell leukemia/lymphoma virus (HTLV) I and II can be transmitted through transfusion, though screening has drastically reduced this risk. 2, 3, 4
Other Viral Pathogens
- Cytomegalovirus (CMV): 30-50% of adults have serologic evidence of past infection, posing risks to immunocompromised recipients and pregnant women 2, 3
- Epstein-Barr virus (EBV): Can cause lymphoproliferative disorders in immunocompromised patients 3
- Parvovirus B19: May cause severe infections in pregnant women and immunodeficient individuals 2
Parasitic and Other Infections
Malaria, Chagas disease, and variant Creutzfeldt-Jakob disease cannot currently be detected by standard screening tests. 1 These remain potential risks in endemic areas or from donors with relevant exposure history.
- Plasmodium species (malaria) 4
- Trypanosoma cruzi (Chagas disease) 1, 4
- Toxoplasma gondii 4
- Treponema pallidum (syphilis): Seropositivity rate of 0.02% in screened donors 4, 5
Critical Clinical Pitfall
The most important caveat is that general anesthesia may mask symptoms of transfusion reactions, including fever, chills, and urticaria that would alert clinicians to bacterial contamination or other infectious complications. 1, 6 Therefore, periodic monitoring for signs including hypotension, tachycardia, hyperthermia, and decreased urine output is essential even in anesthetized patients. 1