Yersinia enterocolitica is most likely responsible for septic reactions in transfusions of Red Blood Cells. This organism is usually acquired by ingestion of contaminated food and causes mild symptoms of abdominal pain and diarrhea. Growth of Y. enterocolitica is enhanced in iron-rich environments such as red blood cells. Other organisms reportedly found in Red Blood Cell units are Campylobacter species, Serratia species, Pseudomonas species, Enterobacter species, and Escherichia coli. These bacteria can produce endotoxins, which cause a reaction in the patient.
The majority of organisms associated with Platelet transfusions are normal skin flora. Staphylococcus aureus, coagulase-negative staphylococci, aerobic and anaerobic diptheroid bacilli, streptococci, and gram-positive bacilli are frequently isolated. Some transfused organisms have been implicated in a delayed post-transfusion illness.
Pseudomonas aeruginosa and Burkholderia cepacia have been isolated in CRYO and FFP. These organisms grow optimally at 30°C and have been found in water baths, accentuating the importance of overwrapping components that are thawed in a water bath.
Rickettsia species are intracellular bacteria that are transmitted by ticks or insects. These bacteria are the causes of Rocky Mountain Spotted Fever, Ehrlichiosis, and scrub typhus. These organisms may also be transmitted through transfusion.