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

405 nm light microbicidal efficacy on Treponema pallidum spiked in ex vivo human platelets

Pathogen reduction technologies using chemicals and or UV light have been demonstrated to improve the safety of ex vivo platelets from infectious diseases. However, UV light exposure also may affect the treated products, depending on wavelength and exposure. Alternatively, visible spectra 405 nm violet-blue light has broad-spectrum microbicidal activity. Here we tested the effect of 405 nm light on Treponema pallidum, the bacterium that causes syphilis. We contaminated platelets stored in plasma with two treponemal concentrations (low and high titers) and treated an aliquot with 270 J/cm2 dose (irradiance = 15 mW/cm2) of 405 nm light while another aliquot remained untreated. Next, we inoculated intradermally an aliquot of both samples into rabbits. Rabbits inoculated with untreated samples developed syphilis while animals inoculated with light-treated samples did not. Thus, inactivation was demonstrated to the limit of detection of the bioassay. We estimated > 2 log10 and > 4 log10 reduction in the low and high dose studies, respectively. These results provide proof-of-concept that 405 nm light is effective in reducing syphilis risk in ex vivo platelets.

Preliminary determination of bacterial contamination of whole blood units in a Ghanaian blood bank: Providing evidence to improve transfusion safety

BACKGROUND AND OBJECTIVES

Transfusion-associated bacterial sepsis poses a significant risk to patient safety. This study aimed to determine the rate of bacterial contamination of whole blood (WB) collected at the Cape Coast Teaching Hospital (CCTH) as a quality control and quality assurance activity.

MATERIALS AND METHODS

One-hundred and three WB units collected between January and April of 2018 were screened for bacterial contamination. Bacteria isolated from positive cultures were identified and subjected to antimicrobial testing. WB recipients were followed up for clinical symptoms.

RESULTS

Of the 103 WB units tested, 33 (32%) were contaminated with bacteria. Gram-positive organisms accounted for 67% of the isolates, including coagulase-negative Staphylococcus, Staphylococcus aureus and Bacillus spp., while Gram-negative bacteria comprised 33% of the isolates, with Citrobacter freundii, Serratia marcescens, Escherichia coli and Providencia stuartii being identified. Resistance to antibiotics varied between species. No septic transfusion events were reported involving WB units tested in this study.

CONCLUSION

The high percentage of contaminated WB units collected at the CCTH provided evidence-based data for the implementation of improved donor skin disinfection processes and the use of blood diversion pouches in 2019. These approaches allowed CCTH to comply with Ghanaian regulatory entities.

Collaboration is key: Case report of suspected Pseudomonas fluorescens transfusion-associated infection

BACKGROUND

We report a case of suspected Pseudomonas fluorescens transfusion-transmitted infection in a 64-year-old female patient with pancreatic adenocarcinoma. The patient developed a biliary obstruction necessitating a drainage catheter, which was complicated by an arterial hemorrhage. Following the transfusion of 1 RBC unit, the patient developed flank pain, chills, and tachycardia.

STUDY DESIGN AND METHODS

The transfusion reaction workup was negative for hemolytic transfusion reaction. However, Gram stains of the implicated RBC unit revealed Gram-negative rods. Fortunately, the patient was already receiving broad-spectrum antibiotics, and preliminary investigation results were available early enough to alert the medical team and adjust antibiotic coverage. The patient was hospitalized in the ICU where she had elevated WBC counts that normalized after the addition of cefepime. The blood collection center was notified.

RESULTS

Both aerobic and anaerobic cultures incubated at 35°C were negative for growth. A subculture and incubation at room temperature (25°C) demonstrated sufficient growth for the identification of Pseudomonas fluorescens by both Vitek-MS MALDI-TOF and Vitek2 biochemical methods.

DISCUSSION

Pseudomonas fluorescens is a Gram-negative rod-shaped bacterium, well-studied as an environmental microbe. It can cause opportunistic infections in humans and was implicated in previous fatal septic transfusion reactions. This report highlights the importance of both standardization in blood product culture protocols and the need for collaboration between microbiology laboratories and transfusion practitioners to optimize the recovery of potentially clinically important fastidious organisms.

A framework towards implementation of sequencing for antimicrobial-resistant and other health-care-associated pathogens

Antimicrobial resistance continues to be a growing threat globally, specifically in health-care settings in which antimicrobial-resistant pathogens cause a substantial proportion of health-care-associated infections (HAIs). Next-generation sequencing (NGS) and the analysis of the data produced therein (ie, bioinformatics) represent an opportunity to enhance our capacity to address these threats. The 3rd Geneva Infection Prevention and Control Think Tank brought together experts to identify gaps, propose solutions, and set priorities for the use of NGS for HAIs and antimicrobial-resistant pathogens. The major deliverable recommendation from this meeting was a proposed framework for implementing the sequencing of HAI pathogens, specifically those harbouring antimicrobial-resistance mechanisms. The key components of the proposed framework relate to wet laboratory quality, sequence data quality, database and tool selection, bioinformatic analyses, data sharing, and NGS data integration, to support public health and actions for infection prevention and control. In this Personal View we detail and discuss the framework in the context of global implementation, specifically in low-income and middle-income countries.

Considerations on risk mitigating strategies for bacterial contamination of platelet concentrates - The Dutch perspective

Due to their storage at room temperature, platelet concentrates are at risk for bacterial outgrowth if the unit is contaminated. Nowadays, various mitigation strategies are available, including bacterial screening and pathogen inactivation. Since pathogen inactivation technologies impact the clinical efficacy of the platelets, including but not limited to lower increments after transfusion and more significant bleeding, a balance needs to be struck between the safety and efficacy of platelet transfusions. In this Brief Review, we discuss the current situation in the Netherlands.

Formation of Single-Species and Multispecies Biofilm by Isolates from Septic Transfusion Reactions in Platelet Bag Model

During 2018-2021, eight septic transfusion reactions occurred from transfusion of platelet units contaminated with Acinetobacter spp., Staphylococcus saprophyticus, Leclercia adecarboxylata, or a combination of those environmental organisms. Whether biofilm formation contributed to evasion of bacterial risk mitigations, including bacterial culture, point-of-care testing, or pathogen-reduction technology, is unclear. We designed a 12-well plate-based method to evaluate environmental determinants of single-species and multispecies biofilm formation in platelets. We evaluated bacteria isolated from septic transfusion reactions for biofilm formation by using crystal violet staining and enumeration of adherent bacteria. Most combinations of bacteria had enhanced biofilm production compared with single bacteria. Combinations involving L. adecarboxylata had increased crystal violet biofilm production and adherent bacteria. This study demonstrates that transfusion-relevant bacteria can produce biofilms well together. More work is needed to clarify the effect of biofilms on platelet bacterial risk control strategies, but US Food and Drug Administration-recommended strategies remain acceptable.

Proliferation of psychrotrophic bacteria in cold-stored platelet concentrates

BACKGROUND AND OBJECTIVES

Platelet concentrates (PC) are stored at 20-24°C to maintain platelet functionality, which may promote growth of contaminant bacteria. Alternatively, cold storage of PC limits bacterial growth; however, data related to proliferation of psychotrophic species in cold-stored PC (CSP) are scarce, which is addressed in this study.

MATERIALS AND METHODS

Eight laboratories participated in this study with a pool/split approach. Two split PC units were spiked with ~25 colony forming units (CFU)/PC of Staphylococcus aureus, Klebsiella pneumoniae, Serratia liquefaciens, Pseudomonas fluorescens and Listeria monocytogenes. One unit was stored under agitation at 20-24°C/7 days while the second was stored at 1-6°C/no agitation for 21 days. PC were sampled periodically to determine bacterial loads. Five laboratories repeated the study with PC inoculated with lyophilized inocula (~30 CFU/mL) of S. aureus and K. pneumoniae.

RESULTS

All species proliferated in PC stored at 20-24°C, reaching concentrations of ≤109 CFU/mL by day 7. Psychrotrophic P. fluorescens and S. liquefaciens proliferated in CSP to ~106 CFU/mL and ~105 CFU/mL on days 10 and 17 of storage, respectively, followed by L. monocytogenes, which reached ~102 CFU/mL on day 21. S. aureus and K. pneumoniae did not grow in CSP.

CONCLUSION

Psychrotrophic bacteria, which are relatively rare contaminants in PC, proliferated in CSP, with P. fluorescens reaching clinically significant levels (≥105 CFU/mL) before day 14 of storage. Cold storage reduces bacterial risk of PC to levels comparable with RBC units. Safety of CSP could be further improved by implementing bacterial detection systems or pathogen reduction technologies if storage is beyond 10 days.

Implementation of amotosalen plus ultraviolet A-mediated pathogen reduction for all platelet concentrates in France: Impact on the risk of transfusion-transmitted infections

BACKGROUND AND OBJECTIVES

Pathogen reduction (PR) technology may reduce the risk of transfusion-transmitted infections (TTIs), notably transfusion-transmitted bacterial infection (TTBI) associated with platelet concentrates (PCs). PR (amotosalen/UVA treatment) was implemented for all PCs transfused in France in November 2017. No bacterial detection was in place beforehand. The study aimed to assess the impact of PR PC on TTI and TTBI near-miss occurrences.

MATERIALS AND METHODS

TTI and TTBI near-miss occurrences were compared before and after 100% PR implementation. The study period ran from 2013 to 2022. Over 300,000 PCs were transfused yearly.

RESULTS

No PC-related transmission of human immunodeficiency virus, hepatitis C virus, hepatitis B virus and human T-cell lymphotropic virus was reported throughout the study period. PC-mediated hepatitis E virus and hepatitis A virus infections occurred irrespective of PR implementation. Mean PC-mediated TTBI occurrence before PR-PC implementation was 3/year (SD: 1; n = 15; 1/92,687 PC between 2013 and 2016) with a fatal outcome in two patients. Since PR implementation, one TTBI has been reported (day 4 PC, Bacillus cereus) (1/1,645,295 PC between 2018 and 2022; p < 0.001). Two PR PC quarantined because of a negative swirling test harboured bacteria: a day 6 PC in 2021 (B. cereus and Staphylococcus epidermidis) and a day 7 PC in 2022 (Staphylococcus aureus). Five similar occurrences with untreated PC were reported between 2013 and 2020.

CONCLUSION

Transfusion of 100% PR PC resulted in a steep reduction in TTBI occurrence. TTBI may, however, still occur. Pathogen-reduced PC-related TTI involving non-enveloped viruses occurs as well.

Bacterial Contamination of Platelet Products

Transfusion of bacterially contaminated platelets, although rare, is still a major cause of mortality and morbidity despite the introduction of many methods to limit this over the past 20 years. The methods used include improved donor skin disinfection, diversion of the first part of donations, use of apheresis platelet units rather than whole-blood derived pools, primary and secondary testing by culture or rapid test, and use of pathogen reduction. Primary culture has been in use the US since 2004, using culture 24 h after collection of volumes of 4-8 mL from apheresis collections and whole-blood derived pools inoculated into aerobic culture bottles, with limited use of secondary testing by culture or rapid test to extend shelf-life from 5 to 7 days. Primary culture was introduced in the UK in 2011 using a "large-volume, delayed sampling" (LVDS) protocol requiring culture 36-48 h after collection of volumes of 16 mL from split apheresis units and whole-blood derived pools, inoculated into aerobic and anaerobic culture bottles (8 mL each), with a shelf-life of 7 days. Pathogen reduction using amotosalen has been in use in Europe since 2002, and was approved for use in the US in 2014. In the US, recent FDA guidance, effective October 2021, recommended several strategies to limit bacterial contamination of platelet products, including pathogen reduction, variants of the UK LVDS method and several two-step strategies, with shelf-life ranging from 3 to 7 days. The issues associated with bacterial contamination and these strategies are discussed in this review.