Platelet transfusions are more likely than any other blood product to cause sepsis. Because platelets are usually stored at room temperature, bacteria in a contaminated unit can multiply to dangerous levels by the time it is transfused. Primary cultures suggest about 1 in every 5,000 platelet collections is contaminated.
Between May and October 2018, four patients in three states developed sepsis after receiving apheresis platelets contaminated with Acinetobacter calcoaceticus-baumannii complex (ACBC) and Staphylococcus saprophyticus. One died.
The four cases
| Patient | Where, when | What happened |
|---|---|---|
| A — man with acute lymphoblastic leukemia | California, May 4 | Given pathogen-reduced platelets. Within minutes, shaking chills; two hours later, fever and low blood pressure. Treated in intensive care for septic shock; recovered. His blood grew ACBC; the bag residue grew ACBC and S. saprophyticus. The platelets came from a donation collected 5 days earlier, treated with pathogen inactivation 13.5 hours after collection. The unit's twin, never transfused, tested negative |
| B — man with cirrhosis and low platelets | Utah, May 10 | Transfused to prevent bleeding before a procedure. Chills an hour in; the transfusion was stopped. Fever, low blood pressure and rapid breathing followed, and he died of septic shock two days later. ACBC grew from his blood and the bag. The donation's primary culture, started 24 hours after collection, had stayed negative for 5 days |
| C and D — two men with acute myeloid leukemia | Connecticut, October 4 | Each got a unit from the same donation, collected in Massachusetts 4 days earlier and processed in Connecticut. Within two hours both had fever and low blood pressure; both went to intensive care and recovered. Both patients' blood and both bags grew ACBC and S. saprophyticus — although the donation had passed primary aerobic and anaerobic culture, and both units had tested negative on a rapid bacterial detection device within 5 hours of transfusion |
Timeline of the four cases. CDC
Searching for a source
- The donors in California, Utah and Massachusetts were different people, with no known links to one another and no sign of illness; all were indefinitely deferred. Skin samples from the California donor, and urine, perianal and skin samples from the Utah donor, were negative.
- The equipment: all three donations were collected into platelet additive solution with apheresis machines and collection sets from the same manufacturer — and two of the three collection sets came from the same lot.
- The environment: ACBC turned up on platelet agitators at the Utah supplier (May 23) and at hospital B (June 7); S. saprophyticus on an agitator at hospital C (November 13). Swabs at the California collection site and hospital A, taken weeks later after cleaning, and at the Connecticut and Massachusetts supplier facilities, found nothing relevant.
- Looking wider: in July, CDC and the Infectious Diseases Society of America's Emerging Infections Network asked for other cases of Acinetobacter sepsis within 24 hours of a platelet transfusion. Three were reported — two in North Carolina, one in Michigan — but their bacteria turned out to be unrelated (13,398–14,289 SNPs apart).
What the genomes showed
- ACBC: 14 isolates — from the blood of all four patients, all four bag residues, and the Utah supplier and hospital B environmental samples — were closely related, differing by 0–32 SNPs across 95.6% of the core genome. They may be a new taxon within the complex, only a 90% match to Acinetobacter seifertii.
- S. saprophyticus formed two clusters: one linking patient C's blood, patient C's bag and the swab from hospital C (0–37 SNPs apart); the other linking patient D's blood with the bags given to patients D and A (1–27 SNPs apart).
Together, this points to an unidentified common source of contamination. The investigation was continuing.
Why it's unusual
- ACBC rarely contaminates platelets. These gram-negative bacteria favor wet places, survive drying, persist on surfaces and cling to plastics — and cause opportunistic infections.
- Coagulase-negative staphylococci are among the commonest platelet contaminants, but S. saprophyticus usually lives in the gut and urinary tract, not on the skin, so it may be less likely than its relatives to get into platelets.
- The usual culprits are the donor's skin bacteria or a donor with bacteria in the blood — but in 1993 a cluster of septic reactions was traced to blood bags contaminated during manufacturing or packaging.
The lesson
The Food and Drug Administration requires blood establishments and transfusion services to control the risk of bacterial contamination, and most U.S. suppliers do it with a primary culture before transfusion. Because sepsis kept happening anyway, extra safeguards have been added: pathogen inactivation, rapid bacterial detection and other culture strategies. This cluster shows that contaminated platelets can still get through — one unit here had been pathogen-inactivated, and two had passed a rapid test after a negative primary culture.
Septic transfusion reactions are severe: of these four patients, one died and three needed intensive care. Clinicians should watch for sepsis after every platelet transfusion, even with these safeguards in place, and report reactions at once to the platelet supplier and to hemovigilance systems.
Sources
Based on Jones SA, Jones JM, Leung V, et al., "Sepsis Attributed to Bacterial Contamination of Platelets Associated with a Potential Common Source — Multiple States, 2018," MMWR volume 68, number 23, Centers for Disease Control and Prevention, with authors from CDC, state health departments, hospitals and blood suppliers; a work of the United States government in the public domain.
许可协议： CC0 1.0（公有领域） · 改编自 www.cdc.gov
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