A Fatal Case of Septic Shock Secondary to Acinetobacter Bacteremia Acquired from a Platelet Transfusion

Posttransfusion Sepsis Attributable to Bacterial Contamination in Platelet Collection Set Manufacturing Facility, United States

During May 2018‒December 2022, we reviewed transfusion-transmitted sepsis cases in the United States attributable to polymicrobial contaminated apheresis platelet components, including Acinetobacter calcoaceticus‒baumannii complex or Staphylococcus saprophyticus isolated from patients and components. Transfused platelet components underwent bacterial risk control strategies (primary culture, pathogen reduction or primary culture, and secondary rapid test) before transfusion. Environmental samples were collected from a platelet collection set manufacturing facility. Seven sepsis cases from 6 platelet donations from 6 different donors were identified in patients from 6 states; 3 patients died. Cultures identified Acinetobacter calcoaceticus‒baumannii complex in 6 patients and 6 transfused platelets, S. saprophyticus in 4 patients and 4 transfused platelets. Whole-genome sequencing showed environmental isolates from the manufacturer were closely related genetically to patient and platelet isolates, indicating the manufacturer was the most probable source of recurrent polymicrobial contamination. Clinicians should maintain awareness of possible transfusion-transmitted sepsis even when using bacterial risk control strategies.

Assessment of polymicrobial interactions in bacterial isolates from transfused platelet units associated with sepsis

BACKGROUND

In 2019 the Centers for Disease Control and Prevention (CDC) reported a series of 4 transfusion reactions that resulted from contamination of apheresis platelet products. Products involved in all 4 cases were contaminated with Acinetobacter calcoaceticus-baumannii complex (ACBC) and in 3 products Staphylococcus saprophyticus was found as well. CDC investigation found that bacterial isolates from the cases were genetically related and suggested a common source of contamination. The contamination of blood products with ACBC is rare and polymicrobial contamination of blood products even less common. ACBC and S. saprophyticus have been observed to adhere to one another and sediment out of suspension in vitro, a process referred to as coaggregation, and we hypothesized that there was an interaction between the strains from these cases that contributed to their co-contamination of blood products.

STUDY DESIGN AND METHODS

To test the hypothesis of bacterial interaction, we performed coaggregation experiments and observed the growth characteristics of ACBC and S. saprophyticus strains recovered from contaminated blood products involved in a subset of the CDC cases.

RESULTS

An increase in S. saprophyticus CFU concentration was observed after several days of co-culture with ACBC in LB and plasma; however, no other findings suggested coaggregation or augmentative growth interaction between the bacterial strains.

CONCLUSION

Ultimately, an interaction between ACBC and S. saprophyticus that could help explain their co-occurrence and growth in contaminated platelet units was not found; however future studies of potential interactions may be warranted.

Acquired platelet storage container leaks and contamination with environmental bacteria: A preventable cause of bacterial sepsis

Background

Apheresis platelets (AP) may be contaminated by environmental bacteria via container defects acquired during processing, transport, storage, or transfusion, as highlighted by a recent series of septic reactions related to Acinetobacter spp. and other bacterial strains.

Study design and methods

The frequency and nature of acquired container defect reports to one manufacturer were evaluated from January 2019 to July 2020. The published incidence of contamination and sepsis due to environmental bacteria with culture screened AP in the United States was reviewed for the period of 2010–2019.

Results

Review of a manufacturers' records showed 23 US reports of leaks involving 24 containers attributed to postmanufacturing damage, at a rate of 44 per million distributed storage containers. Analysis of returned containers showed evidence of scratches, impressions, and/or piercings. Literature review of US hemovigilance data revealed that environmental bacteria comprised 7% of confirmed positive primary bacterial culture screens, were responsible for 14%–16% of reported septic, and 8 of 28 (29%) fatal reactions with bacterial‐culture screened AP. Sepsis cases have been reported with culture screened, point‐of‐issue (POI) tested, or pathogen‐reduced AP.

Discussion

Environmental contamination of AP is rare but can cause sepsis. Container damage provides a pathway for contamination after culture screening, POI bacteria testing, or pathogen reduction. Blood collectors and transfusion services should have procedures to ensure proper inspection, handling, storage, and transport of AP to avoid damage and should enhance efforts to detect defects prior to release and to eliminate bacteria from all contacting surfaces to minimize the risk of contamination.

Limitations of current practices in detection of bacterially contaminated blood products associated with suspected septic transfusion reactions

BACKGROUND

In the setting of suspected septic transfusion reactions, bacterial culture of both the transfused patient and the residual blood component is recommended. Primary bacterial contamination can occur at the time of component collection. Clinically insignificant "secondary contamination" can occur during post-transfusion component discard, retrieval for culture, or manipulation of the bag at the time of culture sampling.

STUDY DESIGN AND METHODS

This retrospective, multi-center study analyzes positive residual component culture results and companion patient blood cultures from 15 hospitals, 1 blood center, and all cultured transfusion reactions within the province of Quebec, Canada, over a 5-year period. Imputability was assigned as "definite" (concordant growth), "possible" (discordant growth or lack of growth in patient culture), or "unable to assess" (patient not cultured).

RESULTS

There were 373 positive component cultures from 360 unique transfusion reactions, with 276 (76.7%) companion patient blood cultures performed, of which 10 (2.8%) yielded the pathogen detected in the positive component. Of these 10 definite pathogens, 7 (2 Staphylococcus aureus, 3 other staphylococci, and 1 Streptococcus pyogenes and 1 Bacillus sp.) were associated with platelet and 3 (Aeromonas veronii, Staphylococcus epidermidis, and Enterococcus faecalis) with RBC transfusions. RBC and plasma components comprised 70% of positive component cultures.

DISCUSSION

The process of performing residual component culture is vulnerable to secondary contamination. The significance of microorganisms recovered from component culture cannot be interpreted in isolation. In the context of low prevalence of primary contamination of blood components, the positive predictive value of a positive component culture result is very low.