Apheresis technology correlates with bacterial contamination of platelets and reported septic transfusion reactions

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.

Supplemental findings of the 2021 National Blood Collection and Utilization Survey

BACKGROUND

The Department of Health and Human Services' National Blood Collection and Utilization Survey (NBCUS) has been conducted biennially since 1997. Data are used to estimate national blood collection and use. Supplemental data from the 2021 NBCUS not presented elsewhere are presented here.

METHODS

Data on survey participation, donor characteristics, blood component cost, transfusion-associated adverse reactions, and implementation of blood safety measures, including pathogen-reduction of platelets, during 2021, were analyzed. Comparisons are made to 2019 survey data where available (2013-2019 for survey participation).

RESULTS

During 2021, there were 11,507,000 successful blood donations in the United States, a 4.8% increase from 2019. Persons aged 45-64 years accounted for 42% of all successful blood donations. Donations by persons aged 65 years and older increased by 40.7%, while donations among minorities and donors aged <25 years decreased. From 2019 to 2021, the median price hospitals paid per unit of leukoreduced red blood cells, leukoreduced and pathogen-reduced apheresis platelets, and fresh frozen plasma increased. The largest increase in price per unit of blood component in 2021 was for leukoreduced apheresis platelets, which increased by ~$51. Between 2019 and 2021, the proportion of transfusing facilities reporting use of pathogen-reduced platelets increased, from 13% to 60%. Transfusion-related adverse reactions declined slightly between 2019 and 2021, although the rate of transfusion-transmitted bacterial infections remained unchanged.

CONCLUSION

During 2021, blood donations increased nationally, although donations from those aged <25 years and minorities declined. The prices hospitals paid for most blood products increased, as did the use of pathogen-reduced platelets.

RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity

Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.

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.

Implementation strategy for complete pathogen reduction technology treated apheresis platelet inventory

BACKGROUND

Bacterial contamination in platelets remain a major public health concern, which prompted the US Food and Drug Administration guidance for bacterial contamination mitigation. Pathogen reduction technology (PRT) is one mitigation strategy that has shown success in Europe over the last decade. Therefore, our center sought to transition from a dual system of bacterial culturing (BacT) and PRT to full PRT.

METHODS

A 1 month pilot study was conducted to simulate 100% PRT conditions. Our center also collected baseline data on key platelet production metrics in the 4 months prior to 100% PRT and compared it to the 4 months post-implementation.

RESULTS

The pilot study showed no statistical differences in split rate, proportion of low-yield products, or proportion of single, double, and triple collections. The only observed difference was an 11 min increase in the average duration of double collections. Our baseline versus post-implementation monitoring showed no difference in split rate, discard rate, percentage of low-yield units, and average yield of low yield units. Statistical differences were detected in the proportion of single, double, and triple collections, as well as the average yield of full dose products. Roughly 20% of our inventory consisted of low-yield products.

DISCUSSION

With suitable mitigation strategies, transitioning to a full PRT inventory may result in higher net margins while not adversely affecting overall platelet production. A pilot study is a good way to project potential effects of switching from a dual BacT and PRT inventory to full PRT, and can be adopted by other centers aiming to make the transition.

Adverse transfusion reactions and what we can do

INTRODUCTION

Transfusions of blood and blood components have inherent risks and the ensuing adverse reactions. It is very important to understand the adverse reactions of blood transfusion comprehensively for ensuring the safety of any future transfusions.

AREAS COVERED

According to the time of onset, adverse reactions of blood transfusion are divided into immediate and delayed transfusion reactions. In acute transfusion reactions, timely identification and immediate cessation of transfusion is critical. Vigilance is required to distinguish delayed responses or reactions that present non-specific signs and symptoms. In this review, we present the progress of mechanism, clinical characteristics and management of commonly encountered transfusion reactions.

EXPERT OPINION

The incidence of many transfusion-related adverse events is decreasing, but threats to transfusion safety are always emerging. It is particularly important for clinicians and blood transfusion staff to recognize the causes, symptoms and treatment methods of adverse blood transfusion reactions to improve the safety. In the future, at-risk patients will be better identified and can benefit from more closely matched blood components.

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.

Transfusion Reactions and Adverse Events

Blood transfusions are generally safe but can carry considerable risks. This review summarizes the different types of transfusion reactions and ways to diagnose and manage them. Symptoms are often overlapping and nonspecific. When a reaction is suspected, it is critical to stop the transfusion immediately and report the reaction to the blood bank, as this can affect the patient's outcome. New evidence-based algorithms of transfusion, newer blood screening methods and donor policies and deferrals, new laboratory testing, electronic verification systems, and improved hemovigilance lead to the avoidance of unnecessary transfusions and decrease the incidence of serious transfusion reactions.

Pathogen-reduced platelets in pediatric and neonatal patients: Demographics, transfusion rates, and transfusion reactions

BACKGROUND

Pathogen-reduced platelets (PR PLT) are the emerging standard for proactive transfusion-transmitted infection (TTI) mitigation. There is, however, continued hesitation to transfuse PR PLT in children due to limited published data. We report demographics, rates of transfusion, and transfusion reactions (TR) associated with FDA-approved PR PLT in pediatric and neonatal patients at an academic medical center.

METHODS

Retrospective review was performed for patients <18 years receiving at least one platelet over a 300-day period at a large, tertiary care hospital. Patients were transfused PR or conventional (CONV) PLT, based on inventory availability. Statistical analysis was performed using Fisher Exact Test.

RESULTS

During the study period, 191 patients received 1010 platelet transfusions (892 units). Sixty-eight patients received PR PLT only (1.3 units/patient, 95% confidence interval [CI] 1.1-1.5; 1.8 transfusions/patient, 95% CI 1.4-2.2), and 56 patients received CONV PLT only (1.4 units/patient, 95% CI 1.1-1.7; 1.6 transfusions/patient, 95% CI 1.3-1.9). Patients with hematologic malignancies undergoing chemotherapy/radiation and allogeneic hematopoietic stem cell transplant received the most platelet transfusions and more commonly received both platelet types. Of 506 PR PLT units, 5 TRs occurred; 386 CONV PLT resulted in two TRs (p = .7052). Of 51 neonates, 37 received PR PLT without adverse events, including 13 receiving phototherapy. No TTIs were identified in any group.

CONCLUSION

There was no significant difference in rates of transfusion or TRs between PR and CONV PLT. Our study provides additional evidence that PR PLT can be transfused to pediatric and neonatal patients without increasing the risk of acute adverse events.

Investigating Transfusion-related Sepsis Using Culture-Independent Metagenomic Sequencing

BACKGROUND

Transfusion-related sepsis remains an important hospital infection control challenge. Investigation of septic transfusion events is often restricted by the limitations of bacterial culture in terms of time requirements and low yield in the setting of prior antibiotic administration.

METHODS

In 3 gram-negative septic transfusion cases, we performed metagenomic next-generation sequencing (mNGS) of direct clinical blood specimens in addition to standard culture-based approaches utilized for infection control investigations. Pathogen detection leveraged IDSeq, a new open-access microbial bioinformatics portal. Phylogenetic analysis was performed to assess microbial genetic relatedness and understand transmission events.

RESULTS

mNGS of direct clinical blood specimens afforded precision detection of pathogens responsible for each case of transfusion-related sepsis and enabled discovery of a novel Acinetobacter species in a platelet product that had become contaminated despite photochemical pathogen reduction. In each case, longitudinal assessment of pathogen burden elucidated the temporal sequence of events associated with each transfusion-transmitted infection. We found that informative data could be obtained from culture-independent mNGS of residual platelet products and leftover blood specimens that were either unsuitable or unavailable for culture or that failed to grow due to prior antibiotic administration. We additionally developed methods to enhance accuracy for detecting transfusion-associated pathogens that share taxonomic similarity to contaminants commonly found in mNGS library preparations.

CONCLUSIONS

Culture-independent mNGS of blood products afforded rapid and precise assessment of pathogen identity, abundance, and genetic relatedness. Together, these challenging cases demonstrated the potential for metagenomics to advance existing methods for investigating transfusion-transmitted infections.

Transfusion-related adverse reactions: Data from the National Healthcare Safety Network Hemovigilance Module - United States, 2013-2018

BACKGROUND

Despite current blood safety measures, transfusion recipients can experience transfusion-related adverse reactions. Monitoring these reactions can aid in understanding the effectiveness of current transfusion safety measures. Data from the National Healthcare Safety Network Hemovigilance Module were used to quantify adverse reaction risk.

METHODS

Facilities reporting at least one month of transfused blood components and transfusion-related adverse reactions during January 2013-December 2018 were included. Adverse reaction rates (number per 100,000 components transfused) were calculated for transfused components stratified by component type, collection, and modification methods.

RESULTS

During 2013-2018, 201 facilities reported 18,308 transfusion-related adverse reactions among 8.34 million blood components transfused (220/100,000). Adverse reactions were higher among apheresis (486/100,000) and pathogen-reduced platelets (579/100,000) than apheresis red blood cells (197/100,000). Allergic reactions (41%) were most common. There were 23 fatalities and 9% of all adverse reactions were serious (severe, life-threatening, or fatal). Reactions involving pulmonary complications (transfusion-associated circulatory overload, transfusion-related acute lung injury and transfusion-associated dyspnea) accounted for 35% of serious reactions but 65% of fatalities. Most (76%) of the 37 transfusion-transmitted infections were serious; none involved pathogen-reduced components.

CONCLUSIONS

One in 455 blood components transfused was associated with an adverse reaction although the risk of serious reactions (1 in 6224) or transfusion-transmitted infections (1 in 225,440) was lower. Some serious reactions identified were preventable, suggesting additional safety measures may be beneficial. Higher reaction rates identified among pathogen-reduced platelets require further study. These findings highlight the importance of monitoring reactions through national hemovigilance to inform current safety measures and the need for strategies to increase healthcare facility participation.

A Comparison of Transfusion-Related Adverse Reactions Among Apheresis Platelets, Whole Blood-Derived Platelets, and Platelets Subjected to Pathogen Reduction Technology as Reported to the National Healthcare Safety Network Hemovigilance Module

Despite advances in transfusion safety, concerns with safety of platelet transfusions remain including platelet-related sepsis and higher reaction rates observed among patients receiving apheresis platelets (APLTs). National Healthcare Safety Network (NHSN) Hemovigilance Module (HM) data were analyzed to quantify the burden and severity of adverse reactions occurring from APLTs and whole blood-derived platelets (WBD-PLTs). Facilities participating in NHSN HM during 2010-2018 were included. Adverse reaction rates (number per 100,000 components transfused) were calculated for APLTs and WBD-PLTs stratified by severity, use of platelet additive solution (PAS), and pathogen reduction technology (PRT). Chi-square tests were used to compare rates. During the study interval, 2,000,589 platelets were transfused: 1,435,154 APLTs; 525,902 WBD-PLTs; and among APLTs, 39,533 PRT-APLTs. APLT adverse reaction rates were higher (478 vs 70/ 100,000, P< .01) and more often serious (34 vs 6/100,000; P< .01) compared with WBD-PLTs. Adverse reactions were higher among PRT-APLTs (572/100,000) and were less often serious (18/100,000) compared with non-PRT-APLTs (35/100,000) although this association was not statistically significant. Among components implicated in adverse reactions, 92% of APLTs were suspended in plasma. Compared with PRT-APLTs stored in PAS, rates were higher among units stored in plasma (760 vs 525/100,000). Most serious reactions (75%) were allergic. No transfusion-transmitted infections were reported among PRT-APLTs. APLTs were associated with a 6-fold and 2-fold higher serious adverse reaction risks compared with WBD-PLTs and PRT-APLTs, respectively. These findings demonstrate the importance of monitoring transfusion-related adverse reactions to track the safety of platelet transfusions and quantify the impact of mitigation strategies through national hemovigilance systems.

Fatal sepsis associated with a storage container leak permitting platelet contamination with environmental bacteria after pathogen reduction

BACKGROUND

Pathogen reduction technology and enhanced bacterial culture screening promise to significantly reduce the risk of transfusion-associated septic reactions due to contaminated platelets. Recent reports suggest that these interventions lack efficacy for post-collection and processing contamination with environmental organisms if the storage bag integrity is compromised.

CASE REPORT

We report a fatal septic transfusion reaction in a 63-year-old patient with chronic kidney and liver disease who received a pathogen reduced platelet transfusion in anticipation of surgery.

METHODS

The residual platelet concentrate was cultured, with the detected microorganisms undergoing 16S genotype sequencing. Separate pathogen reduction studies were performed on the recovered bacteria, including assessment for amotosalen photoproducts. The storage container was subjected to pressure testing and microscopic examination. Environmental culture screening was performed at the hospital.

RESULTS

Gram negative rods were detected in the platelet unit and cultures of both platelet component and the patient's blood grew Acinetobacter baumannii complex, Leclercia adecarboxylata and Staphylococcus saprophyticus. These strains were effectively inactivated with >7.2, 7.7, and >7.1 log₁₀ kill, respectively. The platelet storage container revealed a leak visible only on pressure testing. Hospital environmental cultures were negative and the contamination source is unknown. A. baumannii complex and S. saprophyticus 16S genotyping sequences were identical to those implicated in a previously reported septic reaction.

CONCLUSION

Findings are compatible with post-processing environmental contamination of a pathogen reduced platelet concentrate via a non-visible, acquired storage container leak. Efforts are warranted to actively prevent damage to, and detect defects in, platelet storage containers, and to store and transport components in clean environments.

Quality validation of platelets obtained from the Haemonetics and Trima Accel automated blood-collection systems

BACKGROUND

Platelet transfusion is required to treat haemo-oncology or trauma patients. Platelet apheresis (PA) performed with apheresis equipment has increased rapidly in recent years. Leucocyte-reduced platelet apheresis (LRPA) can reduce the risk of platelet refractoriness and febrile nonhemolytic transfusion reactions (FNHTRs) for transfusion. Accordingly, this study aimed to investigate and compare the platelet metabolic and functional responses between PA performed with Haemonetics and LRPA performed with Trima Accel cell separator.

METHODS

The qualities of platelets collected through PA and LRPA were evaluated in terms of visual appearance, morphology, platelet-aggregation changes, metabolic activities, and bacterium-screening test during 5-day storage. Statistical analyses included two-sample t-test and generalised estimating equation(GEE) method.

RESULTS

During 5-day storage in LRPA, residual leucocytes were all <1.0×10⁶, and the parameters of platelet function were as follows: platelet aggregated to agonists such as adenosine 5'-diphosphate (ADP) and collagen, and the extent of shape change and pO₂ showed no statistically significant difference between PA and LRPA. The hypotonic shock reaction (HSR) on days 0, 1, and 3 were significantly higher in LRPA than in PA (71.78±6.92 vs. 64.10±7.42; P=0.002; 71.53±8.98 vs. 62.96±9.84; P=0.007; 68.05±7.28 vs. 57.76±6.80; P<0.0001, respectively). Values of mean platelet volume (MPV) were statistically larger in PA than in LRPA on days 0, 1, and 3. On day 5, the swirling score was higher in LRPA than in PA. The mean lactate levels had no statistically significant difference between PA and LRPA. Moreover, no growth was observed through bacterium-screening test conducted on 40 samples.

CONCLUSION

Comparison of LRPA and PA products collected from the Trima Accel and Haemonetics automated blood-collection systems, respectively, revealed that both products possessed good platelet qualities even though additional processes are needed to reduce leucocytes. Furthermore, investigating the outcomes of other apheresis instruments with focus on the safety of donors, products, and recipients is necessary.

Sepsis from an apheresis platelet contaminated with Acinetobacter calcoaceticus/baumannii complex bacteria and Staphylococcus saprophyticus after pathogen reduction

BACKGROUND

Strategies to reduce platelet (PLT) bacterial contamination include donor screening, skin disinfection, sample diversion, bacterial culture, pathogen reduction (PR), and day-of-transfusion tests. We report bacterial sepsis following a pathogen-reduced PLT transfusion.

CASE REPORT

An adult male with relapsed acute lymphoblastic leukemia was successfully treated for central catheter-associated Staphylococcus aureus bacteremia. A peripherally inserted central catheter (PICC) was placed. Chills, rigors, and flushing developed immediately after PICC-infused pathogen-reduced PLTs, progressing to septic shock requiring intensive care management.

METHODS

PICC and peripheral blood (PB), transfused bag saline flushes (TBFs), environmental samples, and the pathogen-reduced untransfused co-component (CC) were cultured. Plasma metagenomic and bacterial isolate whole-genome sequencing; PLT mitochondrial DNA (mtDNA) testing of untransfused CC and TBF; CC testing for amotosalen (S-59)/S-59 photoproducts; isolate PR studies (INTERCEPT); and TBF polymerase chain reaction for recipient Y-chromosome DNA were performed.

RESULTS

PB and PICC cultures grew Acinetobacter calcoaceticus/baumannii complex (ACBC). TBF was gram-positive; mass spectrometry identified ACBC and Staphylococcus saprophyticus (SS). CC Gram stain and cultures were negative. Environmental cultures, some done after decontamination, were ACBC/SS negative. Posttransfusion patient plasma and TBF ACBC sequences were genetically identical. No Y-chromosome signal was detected in TBF. S-59 photoproducts and evidence of mtDNA amplification inhibition were found in the CC. Spiking PR studies showed >5.9-log inactivation for both isolates. Donor skin cultures for Acinetobacter were negative.

CONCLUSION

CC sterility, PR studies, residual S-59 photoproducts, and mtDNA amplification inhibition suggest successful PR. Unidentified environmental sources and inherent or acquired bag defects may have contributed to postmanufacturing pathogen-reduced PLT contamination.

Pathogen reduction of double-dose platelet concentrates from pools of eight buffy coats: Product quality, safety, and economic aspects

Background

Pathogen reduction (PR) of platelet concentrates (PCs) contributes to the safety of platelet (PLT) transfusion by reducing the risk of transfusion‐transmitted infections and transfusion‐associated graft‐versus‐host disease. In vitro quality of pathogen‐reduced double‐dose PC (PR‐PC) made of eight whole blood (WB)‐derived buffy coats (BCs) were evaluated.

Methods

Eight small‐volume WB BCs from donors with at least 200 × 10⁹ PLT/L were pooled with an additive solution to produce double‐dose PCs (DD‐PCs), which were treated with amotosalen/ultraviolet A light in a dual storage processing set, yielding 2 units of PR‐PC. Quality controls were undertaken as per European Directive for the Quality of Medicines (EDQM) guidelines. PLT recovery rates were measured. Production costs and savings were compared over the 3 years before and after PR implementation.

Results

In the pre‐PR period, 19 666 PCs were produced, compared to 17 307 PCs in the PR period. Single BC in the PR period had 41 ± 2 mL, hematocrit 0.39 ± 0.04 and 1.06 ± 0.18 × 10¹¹ PLTs, and showed a recovery of 91% ± 8%. After pooling, separation, PR treatment of DD‐PC, and splitting, each single PC had 189 ± 6 mL with 2.52 ± 0.34 × 10¹¹ PLTs, compared to 2.48 ± 0.40 in the pre‐PR period. The PLT recovery rate after PR was 87% ± 14%. EDQM requirements were met. An increase of about €12 (+7.5%) per PC from the pre‐PR to the PR period was identified.

Conclusion

A new production method resulting in two PR‐PCs made from pools of 8 BCs with use of one PR set was successfully introduced, and our experience of nearly 3 years demonstrated the high efficacy and in vitro quality of the PR‐PCs obtained.

Different growth kinetics in blood components and genetic analysis of Lactococcus garvieae isolated from platelet concentrates

BACKGROUND

In 2014, we experienced the first isolation of Lactococcus garvieae from a platelet concentrate (PC). Thereafter, L. garvieae contamination of PCs occurred in two more cases in Japan. It is rare that bacterial contamination with uncommon strains like this species occurs frequently within a short period. Therefore, we performed a detailed analysis of the characteristics of these strains.

STUDY DESIGN AND METHODS

Three bacterial strains were identified by biochemical testing and molecular analysis. Genomic diversity was characterized by multilocus sequence typing (MLST). To observe growth kinetics in blood components, PCs were inoculated with the three different strains.

RESULTS

All three strains were identified as L. garvieae by molecular analysis. Each strain belonged to a different phylogenetic group according to MLST analysis. In the spiking trial, the three strains demonstrated differences in their final concentrations and changes in appearance of PCs.

CONCLUSION

In this study, all three L. garvieae strains were correctly identified by molecular analysis. Since the three strains were collected in different regions of Japan and belonged to different phylogenetic groups according to MLST analysis, it is suggested that L. garvieae have a wide distribution with diversity in Japan. In PCs, the three L. garvieae strains showed clear differences in growth kinetics and changes in appearance of PCs. These differences may have been the primary determinant of whether PC contamination was detected before transfusion. Moreover, L. garvieae represents an emerging foodborne bacterium that can cause transfusion-transmitted bacteremia. Understanding our cases may help prevent bacterial contamination of blood products.

Bacterial contamination rate of platelet components by primary culture: a systematic review and meta-analysis

BACKGROUND

Platelets have the highest bacterial contamination risk of all blood components, and septic transfusion reactions remain a problem. A good estimate of contamination rates could provide information about residual risk and inform optimal testing strategies. We performed a systematic review and meta-analysis of platelet contamination rates by primary culture.

STUDY DESIGN AND METHODS

A literature search in December 2019 identified articles on platelet contamination rates using primary culture. We used meta-analysis to estimate the overall rate of contamination and meta-regression to identify heterogeneity. We studied the following sources of heterogeneity: collection method, sample volume, positivity criteria, and study date. Contamination rate estimates were obtained for apheresis (AP), platelet rich plasma (PRP), and buffy coat (BC) collection methods.

RESULTS

The search identified 6102 studies, and 22 were included for meta-analysis. Among these 22 studies, there were 21 AP cohorts (4,072,022 components), 4 PRP cohorts (138,869 components), and 15 BC cohorts (1,474,679 components). The overall mean contamination rate per 1000 components was 0.51 (95% CI: 0.38-0.67) including AP (0.23, 95% CI: 0.18-0.28), PRP, (0.38, 95% CI: 0.15-0.70), and BC (1.12, 95% CI: 0.51-1.96). There was considerable variability within each collection method. Sample volume, positivity criteria, and publication year were significant sources of heterogeneity.

CONCLUSION

The bacterial contamination rate of platelets by primary culture is 1 in 1961. AP and PRP components showed a lower contamination rate than BC components. There is clinically significant between-study variability for each method. Larger sample volumes increased sensitivity, and bacterial contamination rates have decreased over time.

Bacterial contamination and septic transfusion reaction rates associated with platelet components before and after introduction of primary culture: experience at a US Academic Medical Center 1991 through 2017

BACKGROUND

The high incidence of septic transfusion reactions (STRs) led to testing being mandated by AABB from 2004. This was implemented by primary culture of single-donor apheresis platelets (APs) from 2004 and prestorage pooled platelets (PSPPs) from 2007.

STUDY DESIGN/METHODS

Platelet (PLT) aliquots were cultured at issue and transfusion reactions evaluated at our hospital. Bacterial contamination and STR rates (shown as rates per million transfusions in Results) were evaluated before and after introduction of primary culture by blood centers that used a microbial detection system (BacT/ALERT, bioMerieux) or enhanced bacterial detection system (eBDS, Haemonetics).

RESULTS

A total of 28,457 PLTs were cultured during pre-primary culture periods (44.7% APs; 55.3% at-issue pooled PLTs [AIPPs]) and 97,595 during post-primary culture periods (79.3% APs; 20.7% PSPPs). Forty-three contaminated units were identified in preculture and 34 in postculture periods (rates, 1511 vs. 348; p < 0.0001). Contamination rates of APs were significantly lower than AIPPs in the preculture (393 vs. 2415; p < 0.0001) but not postculture period compared to PSPPs (387 vs. 198; p = 0.9). STR rates (79 vs. 90; p = 0.98) were unchanged with APs but decreased considerably with pooled PLTs (826 vs. 50; p = 0.0006). Contamination (299 vs. 324; p = 0.84) and STR rates (25 vs. 116; p = 0.22) were similar for PLTs tested by BacT/ALERT and eBDS primary culture methods. A change in donor skin preparation method in 2012 was associated with decreased contamination and STR rates.

CONCLUSION

Primary culture significantly reduced bacterial contamination and STR associated with pooled but not AP PLTs. Measures such as secondary testing near time of use or pathogen reduction are needed to further reduce STRs.

Bacterial contamination rates in extracorporeal photopheresis

BACKGROUND

Extracorporeal photopheresis (ECP) is an immunosuppressive treatment that involves leukocyte apheresis, psoralen and UV light treatment, and subsequent reinfusion. Patients treated with ECP are usually immunosuppressed. Bacterial contamination therefore poses a much unwanted risk, but incidence data are lacking.

PATIENTS AND METHODS

We screened all 1922 consecutive ECP procedures scheduled within a roughly 3-year period for eligibility. Those with missing data on ECP method (inline or offline) or type of venous access (peripheral or central) were excluded. ECPs with complete aerobic and anaerobic microbial testing of baseline patient blood samples (n = 1637) and of ECP cell concentrates (n = 1814) were included in the analysis.

RESULTS

A test for microbial contamination was positive for 1.82% of the cell concentrates, with central venous access was the most significant risk factor for the contamination (odds ratio = 19). Patient blood samples were positive in 3.85% of cases, but no patients became septic. Staphylococcus spp. were most abundant, and products with bacterial contamination did not cause side effects after reinfusion. There were no significant differences in contamination rates between inline and offline ECP.

CONCLUSION

These findings stress the importance of sterile procedures and the benefits of using peripheral over central venous access for reducing the risk of bacterial contamination in ECP.

Platelet safety strategies in Japan: impact of short shelf life on the incidence of septic reactions

BACKGROUND

Transfusion-transmitted bacterial infections (TTBIs) often have serious consequences for patients. The Japanese Red Cross (JRC) has not implemented culture screening for platelet concentrate (PC), but it has maintained a shelf life of 85 hours for PC.

STUDY DESIGN AND METHODS

The JRC collected reports of suspected TTBI and investigated causal relationships using PC samples and patient blood samples. PCs showing apparent abnormalities were retrieved and cultured and analyzed for bacterial growth.

RESULTS

The JRC analyzed 86 samples available from 135 transfused PCs with suspected TTBIs that were collected over the past 12 years; 17 (19.8%) were culture-positive. One, 6, and 10 TTBIs developed in patients on Days 1, 2, and 3 after PC collection, respectively. Assuming that PC is transfused on the day of issue, the TTBI risk was fourfold higher on Day 3 than on Day 2, after adjusting the TTBI incidence for the number of PCs issued per day. Compared with the model of issuing all PCs on Day 3, issuing PCs with the current distribution of storage time could have decreased the TTBI incidence by 56%. During the past 8 years, the JRC retrieved 960 PC units because of apparent abnormalities, 2.8% of which were culture-positive.

CONCLUSION

The short shelf life of PC is associated with a low incidence of reported TTBIs, more than half of which occurred on Day 3 relative to earlier time points. Visual inspection of PC before transfusion is crucial in detecting bacterially contaminated PC despite its low positive predictive value.

A suspected septic transfusion reaction associated with posttransfusion contamination of a platelet pool by vancomycin-resistant Enterococcus faecium

BACKGROUND

Vancomycin-resistant enterococci (VRE) are antibiotic-resistant organisms associated with both colonization and serious life-threatening infection in health care settings. Contamination of platelet concentrates (PCs) with Enterococcus can result in transfusion-transmitted infection.

CASE PRESENTATION

This report describes the investigation of a septic transfusion case involving a 27-year-old male patient with relapsed acute leukemia who was transfused with a 5-day-old buffy coat PC pool and developed fever and rigors.

DISCUSSION

Microbiology testing and pulse-field gel electrophoresis (PFGE) was done on patient blood cultures obtained from peripheral and central lines. Microbiology and molecular testing were also performed on the remaining posttransfusion PC pool, which was refrigerated for 24 hours before microbiology testing. Red blood cell (RBC) and plasma units associated with the implicated PCs were screened for microbial contamination. Patient blood cultures obtained from peripheral and central lines yielded vancomycin-resistant Enterococcus faecium. Gram stain of a sample from the platelet pool was negative but coagulase-negative Staphylococcus (CNST) and VRE were isolated on culture. Antibiotic sensitivity and PFGE profiles of several VRE isolates from the patient before and after transfusion, and the PC pool, revealed that all were closely related. Associated RBC and plasma components tested negative for microbial contamination.

CONCLUSIONS

Microbiological and molecular investigations showed a relationship between VRE isolated from the patient before and after transfusion, and therefore it is postulated that a patient-to-PC retrograde contamination (from either blood or skin) occurred. As the CNST isolated from the PC pool was not isolated from patient samples, its implication in the transfusion event is unknown.

Sepsis Attributed to Bacterial Contamination of Platelets Associated with a Potential Common Source - Multiple States, 2018

During May-October 2018, four patients from three states experienced sepsis after transfusion of apheresis platelets contaminated with Acinetobacter calcoaceticus-baumannii complex (ACBC) and Staphylococcus saprophyticus; one patient died. ACBC isolates from patients' blood, transfused platelet residuals, and two environmental samples were closely related by whole genome sequencing. S. saprophyticus isolates from two patients' blood, three transfused platelet residuals, and one hospital environmental sample formed two whole genome sequencing clusters. This whole genome sequencing analysis indicated a potential common source of bacterial contamination; investigation into the contamination source continues. All platelet donations were collected using apheresis cell separator machines and collection sets from the same manufacturer; two of three collection sets were from the same lot. One implicated platelet unit had been treated with pathogen-inactivation technology, and two had tested negative with a rapid bacterial detection device after negative primary culture. Because platelets are usually stored at room temperature, bacteria in contaminated platelet units can proliferate to clinically relevant levels by the time of transfusion. Clinicians should monitor for sepsis after platelet transfusions even after implementation of bacterial contamination mitigation strategies. Recognizing adverse transfusion reactions and reporting to the platelet supplier and hemovigilance systems is crucial for public health practitioners to detect and prevent sepsis associated with contaminated platelets.

Plateletpheresis-associated lymphopenia in frequent platelet donors

More than 1 million apheresis platelet collections are performed annually in the United States. After 2 healthy plateletpheresis donors were incidentally found to have low CD4+ T-lymphocyte counts, we investigated whether plateletpheresis causes lymphopenia. We conducted a cross-sectional single-center study of platelet donors undergoing plateletpheresis with the Trima Accel, which removes leukocytes continuously with its leukoreduction system chamber. We recruited 3 groups of platelet donors based on the total number of plateletpheresis sessions in the prior 365 days: 1 or 2, 3 to 19, or 20 to 24. CD4+ T-lymphocyte counts were <200 cells per microliter in 0/20, 2/20, and 6/20 donors, respectively (P = .019), and CD8+ T-lymphocyte counts were low in 0/20, 4/20, and 11/20 donors, respectively (P < .001). The leukoreduction system chamber's lymphocyte-extraction efficiency was ∼15% to 20% for all groups. Immunophenotyping showed decreases in naive CD4+ T-lymphocyte and T helper 17 (Th17) cell percentages, increases in CD4+ and CD8+ effector memory, Th1, and regulatory T cell percentages, and stable naive CD8+ and Th2 percentages across groups. T-cell receptor repertoire analyses showed similar clonal diversity in all groups. Donor screening questionnaires supported the good health of the donors, who tested negative at each donation for multiple pathogens, including HIV. Frequent plateletpheresis utilizing a leukoreduction system chamber is associated with CD4+ and CD8+ T-cell lymphopenia in healthy platelet donors. The mechanism may be repeated extraction of these cells during plateletpheresis. The cytopenias do not appear to be harmful.

Transfusion-Transmitted Infections Reported to the National Healthcare Safety Network Hemovigilance Module

Transfusion-transmitted infections (TTIs) can be severe and result in death. Transfusion-transmitted viral pathogen transmission has been substantially reduced, whereas sepsis due to bacterial contamination of platelets and transfusion-transmitted babesiosis may occur more frequently. Quantifying the burden of TTI is important to develop targeted interventions. From January 1, 2010, to December 31, 2016, health care facilities participating in the National Healthcare Safety Network Hemovigilance Module monitored transfusion recipients for evidence of TTI and recorded the total number of units transfused. Facilities use standard criteria to report TTIs. Incidence rates of TTIs, including for bacterial contamination of platelets and transfusion-transmitted babesiosis, are presented. One hundred ninety-five facilities reported 111 TTIs and 7.9 million transfused components to the National Healthcare Safety Network Hemovigilance Module. Of these 111 reports, 54 met inclusion criteria. The most frequently reported pathogens were Babesia spp in RBCs (16/23, 70%) and Staphylococcus aureus in platelets (12/30, 40%). There were 1.95 (26 apheresis, 4 whole blood derived) TTIs per 100 000 transfused platelet units and 0.53 TTI per 100 000 transfused RBC components, compared to 0.68 TTI per 100 000 all transfused components. Bacterial contamination of platelets and transfusion-transmitted babesiosis were the most frequently reported TTIs. Interventions that reduce the burden of bacterial contamination of platelets, particularly collected by apheresis, and Babesia transmission through RBC transfusion would reduce transfusion recipient morbidity and mortality. These analyses demonstrate the value and importance of facility participation in national recipient hemovigilance using standard reporting criteria.

Bacterial contamination of platelets for transfusion: strategies for prevention

Platelet transfusions carry greater risks of infection, sepsis, and death than any other blood product, owing primarily to bacterial contamination. Many patients may be at particular risk, including critically ill patients in the intensive care unit. This narrative review provides an overview of the problem and an update on strategies for the prevention, detection, and reduction/inactivation of bacterial contaminants in platelets. Bacterial contamination and septic transfusion reactions are major sources of morbidity and mortality. Between 1:1000 and 1:2500 platelet units are bacterially contaminated. The skin bacterial microflora is a primary source of contamination, and enteric contaminants are rare but may be clinically devastating, while platelet storage conditions can support bacterial growth. Donor selection, blood diversion, and hemovigilance are effective but have limitations. Biofilm-producing species can adhere to biological and non-biological surfaces and evade detection. Primary bacterial culture testing of apheresis platelets is in routine use in the US. Pathogen reduction/inactivation technologies compatible with platelets use ultraviolet light-based mechanisms to target nucleic acids of contaminating bacteria and other pathogens. These methods have demonstrated safety and efficacy and represent a proactive approach for inactivating contaminants before transfusion to prevent transfusion-transmitted infections. One system, which combines ultraviolet A and amotosalen for broad-spectrum pathogen inactivation, is approved in both the US and Europe. Current US Food and Drug Administration recommendations advocate enhanced bacterial testing or pathogen reduction/inactivation strategies (or both) to further improve platelet safety. Risks of bacterial contamination of platelets and transfusion-transmitted infections have been significantly mitigated, but not eliminated, by improvements in prevention and detection strategies. Regulatory-approved technologies for pathogen reduction/inactivation have further enhanced the safety of platelet transfusions. Ongoing development of these technologies holds great promise.

Quality Improvement After Multiple Fatal Transfusion-Transmitted Bacterial Infections

OBJECTIVES

Transfusion-transmitted bacterial infection (TTBI) from platelet components is likely underrecognized and can be fatal. Twenty-four-hour prospective culture was felt to be insufficiently preventive after multiple TTBIs occurred and strategies to improve safety were sought.

METHODS

Two fatal and one severe TTBIs occurred from a split-apheresis platelet donation contaminated with Klebsiella pneumoniae. Improvement opportunities were identified and corrective and preventive action (CAPA) followed.

RESULTS

To mitigate bacterial contamination and improve detection sensitivity, additional prospective culture 48 hours postcollection was implemented. Since implementation, secondary cultures have caught two true positives (0.01%) missed by 24-hour culture. Bacterial testing at issue and pathogen reduction were later implemented as an added layer of safety.

CONCLUSION

While rare, TTBI is a prominent cause of morbidity and mortality from contaminated platelets. The approach to CAPA presented here may lower the risk of future transfusion-transmitted infections but must be weighed against potential added costs.