Bacterial Contamination Of Platelet Products Research Articles

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.

Implementation of helicase-dependent amplification with SYBR Green I for prompt naked-eye detection of bacterial contaminants in platelet products

Platelet transfusions may lead to more significant risks of infection and septic transfusion reactions that can be fatal to the recipient. Platelet products should be screened to limit or detect bacterial contamination before application to patients to minimise any adverse reactions. This study aimed to develop a helicase-dependent amplification (HDA) technique targeting a universal highly conserved bacterial gene, 16S rRNA, in combination with naked-eye detection using SYBR Green I (HDA/SYBR Green I) to detect bacterial contamination in platelet products. Thirty positive samples were obtained from spiked platelet products by five transfusion-relevant bacterial strains and were screened for bacterial contamination by HDA/SYBR Green I. HDA/SYBR Green I showed an enhanced yield of bacterial contaminant detection when performed with medium to late shelf life, Day 2 of storage or later platelet products (98.67% sensitivity and 100% specificity compared to the BACT/ALERT culture system). The limit of detection of HDA/SYBR Green I was 1 ng, and there was no cross-reaction with other organisms that could likely contaminate platelet products. The developed HDA/SYBR Green I assay is rapid and simplistic and only requires an easy-to-find heat box, available in general blood bank laboratories, for the amplification step. This technique is suitable for further development as an alternative method to detect bacterial contamination in platelet products in the near future.

Evaluation of the Efficacy of Flow Cytometry in Detecting Bacterial Contamination in Platelets

Introduction: Bacterial contamination of platelet products is a major risk of infections in blood transfusion. Due to their storage conditions at room temperatures (22 to 24°C), cases of septicemia and even death caused by platelet injection have been reported. Therefore, use of appropriate diagnostic methods can improve the health of this product. In this study, flow cytometry was used to detect contaminated platelet units.
 Methods: This study was a diagnostic interventional type. 15 units of platelet concentrate was prepared at a minimum interval time after production. Staphylococcus epidermidis and Escherichia coli (E. coli) bacteria were each added to 6 platelet bags, with a concentration of 10 CFU / ml, while 3 bags were used as negative control. Platelets were stored in a shaking incubator at 22 - 24°C, for 0, 6, 24 and 48 hour-intervals after inoculation. Samples were then taken at 1 ml volume and evaluated by flow cytometry.
 Results: The sensitivity of the flow cytometry method to detect contaminated platelet units in infections with both Staphylococcus epidermidis and E. coli, in a 1 ml volume in all samples at 0, 6, 22 and 24 hours after inoculation, was 100%, and the number of bacteria increased in 24 hours of incubation, except for E. coli that decreased after 24 hours.
 Conclusion: This study shows that flow cytometry can be a useful method for detecting bacterial contamination in platelets, and can detect low concentrations (10 CFU / ml) of bacteria in small volumes of sample (ml) in a short time.

Frequency of bacterial contamination of platelet products in blood transfusion organization of Jahrom in 2016-17

Frequency of bacterial contamination of platelet products in blood transfusion organization of Jahrom in 2016-17

Bacterial contamination of platelet products in Dongguan Blood Center, Guangdong Province of China

Background: Due to the importance of their preservation and collection methods, it is critical to assess accurately the risk of bacterial contamination of pooled platelets and apheresis platelets. The incidence of bacterial contamination was observed after four preventive measures (FPM) (including: sterilizing donation environment, screening donors, depleting white blood cells from pooled platelets, and removing the first 15 ml of collected platelet) were taken. Methods: Platelet product samples (pooled and apheresis platelet products) from Dongguan Blood Center were tested by bacterial cultures including initial culture, subculture and identification. If initial culture was positive, subculture would be performed, and if subculture was positive, bacterial identification would be done. 3073 platelet samples were examined in 2006. Platelet samples were collected in 2006 and in 2007 until 2016 after the introduction of FPM. Recipient’s blood and transfused platelets were tested for bacterial cultures when adverse reactions occurred after platelet transfusion. Results: In 2006, 0.72% and 0.47% bacterial contamination were found in pooled platelets and apheresis platelets, respectively. A total of 63 out of 28,711 (0.22%) bacterial contaminations were detected from 2006 to 2016 in pooled and apheresis platelets. From 2007 to 2016, the positive rates of contaminated platelet products declined significantly to 0.33% (pooled platelets) and 0.14% (apheresis platelets). Only 44 positive samples could be identified after the introduction of FPM. In 50 patients with post-platelet transfusion adverse reaction, no bacterial contamination could be identified. Conclusions: Our study demonstrated the improvement of platelet transfusion safety by FPM, The rate of bacterial contamination in pooled platelets is higher than that of apheresis platelets.

Implications of the US Food and Drug Administration draft guidance for mitigating septic reactions from platelet transfusions.

In March 2016, the US Food and Drug Administration (FDA) issued the second draft guidance entitled “Bacterial Risk Control Strategies for Blood Collection Establishments and Transfusion Services to Enhance the Safety and Availability of Platelets for Transfusion.”1 This draft guideline addresses the residual risk of bacterial contamination of platelet products, which may result in septic transfusion reactions. Among blood products, platelet products are most frequently associated with septic transfusion reactions, as they are stored at room temperature. Since 2004, multiple steps have been implemented to decrease the risk of contamination. These include skin cleansing, diversion pouch, and bacterial screening. These steps have decreased the rate of septic reactions from a reported range of 10 to 400 to 7 to 25 per 1 000 000, and the rate of fatal septic reactions from a reported range of 2 to 63 to 2 to12 per 1 000 000 apheresis platelet products transfused.2 Thus, the overall risk has decreased by approximately two thirds. In the last couple of years, additional steps to decrease risk of septic reactions have been FDA approved, including pathogen-reduction technologies (PRT) and point-of-issue (POI) (also known as point-of-release) testing capabilities. At the New York Blood Center (NYBC), the residual risk as reported from hospitals is septic reaction rate of 1 per 250 065.3 Recent data using prospective testing report 20 per 51 400 (1/2570) platelet products contaminated resulting in 4 per 51 400 (1/12 800) reactions (1 being fatal [1/51 400]).4 PRT decreases most bacteria load by >4 logs. Hemovigilance data have not reported septic transfusion cases with pathogen-reduced (PR) platelets.5 Prospective screening of apheresis platelets using the Pan Genera Detection (PGD) test (Verax Biomedical, Marlborough, MA), a POI test, demonstrated a residual bacterial contamination risk of 1 per 2302 (75% detected with PGD) apheresis platelets. The PGD has a false positive rate of 0.51% and a false negative rate of 1 in 9206.6 The FDA-reported fatality rates due to bacteria contamination of platelets (both pooled and apheresis) range from 1 to 4 per year from 2011 to 2015 in ∼2.1 million annual platelets transfused.7,8 Staphylococcus aureus was the contaminant in the majority of contaminated apheresis platelets. The FDA draft guidance asks for implementation of PRT, POI testing, or a second bacterial culture, or to shorten the shelf life of the platelet product from 5 to 3 days. Each of these methods has considerable logistical and clinical issues. In June 2016, during the open comment period, the NYBC, as well as other blood centers, including AABB (formerly known as the American Association of Blood Banks) and ABC (America’s Blood Centers), expressed their opinions regarding the impact of implementing the draft guidance as written (https://www.regulations.gov/docket?D=FDA-2014-D-1814). We have recently submitted additional comments and have urged the FDA to reopen the comment period to encourage a broader community to remark. Options for meeting these new guidelines based upon days from collection are shown in Table 1. Once the guidance is finalized, there is a proposed 1-year implementation date. Table 1. Platelet product shelf-life and draft guidance options

Bacterial contamination of platelet products in the Blood Transfusion Center of Isfahan, Iran.

Aim: Overall the risk of transfusion transmitted infections has decreased, especially viral infections like HIV and hepatitis B and C. Bacterial contamination of blood and its cellular components, however, remains a common microbiological cause of transfusion associated morbidity and mortality. Platelets pose a special risk given their preservation methods. The incidence of these episodes needs to be assessed and updated on regular basis to accurately manage the risk of transfusion transmitted bacterial infections.Method: 2,000 platelet samples from the Blood Transfusion Center of Isfahan were examined randomly during a 5-month period by bacterial culture and molecular tests. Four platelet samples were found to be contaminated with bacteria, giving a rate of contamination of 500 (0.2%) of tested platelets. Isolated bacteria included one each of Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus. Conclusion: Our study underlines the need for additional safety procedures like bacterial screening and pathogen reduction technology to further decrease the risk of transfusion associated bacterial infections.

Survey of methods used to detect bacterial contamination of platelet products in the United States in 2011

Testing of platelets (PLTs) for bacterial contamination is required by the AABB Standards but is not fully standardized. On January 31, 2011, a new AABB Standard, 5.1.5.1.1, specified that bacterial detection methods for PLT components shall use assays either approved by the Food and Drug Administration (FDA) or validated to provide sensitivity equivalent to these FDA-approved methods. An Internet-based survey of AABB member institutions was conducted from May to June 2012, to document current practices used in 2011 for bacterial detection in different PLT products and to assess the impact of the new standard. Of 1053 AABB member institutions surveyed, 40 of 99 blood centers (40.4%) and 184 of 954 hospital blood banks or transfusion services (19.3%) responded. Sixty-four respondents manufactured PLTs. Apheresis PLTs (APs) were predominantly screened with the BacT/ALERT system (89.5%); the majority (95.2%) were cultured with at least 8 mL of product. There was substantial variation in the minimum incubation time of cultures before release of PLTs (range, 0 to >24 hr). Recalls of released AP for possible bacterial contamination were largely successful (67.3%); successful interdiction before transfusion was associated with incubation for more than 12 hours before release (p < 0.01). After Standard 5.1.5.1.1 took effect, there was a decrease in production of whole blood-derived PLT concentrates (WBPCs). Point-of-issue ("rapid") immunoassays were used to screen a substantial proportion of WBPC PLTs, but were rarely used as secondary tests for previously cultured APs. The survey identified variability in culture methods and release times with AP, while use of WBPC decreased after AABB Standard 5.1.5.1.1 became effective.

FDA contributions to reduction of bacterial contamination in platelet products within the United States

TransfusionVolume 53, Issue 1 p. 232-233 Letters to the Editor FDA contributions to reduction of bacterial contamination in platelet products within the United States Jay S. Epstein MD, Corresponding Author Jay S. Epstein MD Office of Blood Research and Review, Center for Biologics Evaluation and Review, FDA, Rockville, MD[email protected]Search for more papers by this authorJaroslav G. Vostal MD, PhD, Corresponding Author Jaroslav G. Vostal MD, PhD Office of Blood Research and Review, Center for Biologics Evaluation and Review, FDA, Rockville, MD[email protected]Search for more papers by this author Jay S. Epstein MD, Corresponding Author Jay S. Epstein MD Office of Blood Research and Review, Center for Biologics Evaluation and Review, FDA, Rockville, MD[email protected]Search for more papers by this authorJaroslav G. Vostal MD, PhD, Corresponding Author Jaroslav G. Vostal MD, PhD Office of Blood Research and Review, Center for Biologics Evaluation and Review, FDA, Rockville, MD[email protected]Search for more papers by this author First published: 08 January 2013 https://doi.org/10.1111/j.1537-2995.2012.03809.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume53, Issue1January 2013Pages 232-233 RelatedInformation

A Non-Invasive Method for the Detection of Bacterial Contamination of Platelet Apheresis Concentrates

AbstractAbstract 1177 Introduction:Allogeneic blood transfusion is a potential source of infection via a variety of known and unknown transmissible agents. Over the last three decades, pre-transfusion donor screening for viral agents has led to a dramatic reduction in the risk of virally transmitted diseases. Bacterial contamination, on the other hand, has proved more difficult to address and remains the most prevalent transfusion-associated infectious risk. This is especially true for platelet components whose storage conditions (22°C, for up to 5 days, with agitation) facilitate bacterial proliferation throughout the storage period. Reported here are the results of initial testing using a novel, noninvasive, real time, rapid screening device for the detection of bacterial contamination of platelet units. Methods and Results:This detection method is based on measuring absorption of an infrared beam that is transmitted through the gaseous atmosphere above the platelets. Living microorganisms produce metabolic gases such as carbon dioxide (CO2) during respiration. By means of infrared absorption the concentration of metabolic gases can be measured inside the platelet storage bag.The methodology consists of an apparatus which uses a tunable monochromatic mid-IR light source, IR detector and electronic signal processor. The light source emits light in frequency range overlapping at least with one absorption line of CO2gas. Use of the tunable light source allows the determination of metabolic gas concentration within the container without etalon use. In this method, the light from the light source is transmitted through the gaseous part of storage bag is measured by means of an IR detector. The concentration of CO2gas inside the platelet bag is determined by equilibrium conditions between the release rate and the rate of diffusion of the metabolic gases through the bag walls.Staphylococcus epidermidis obtained from the American Type Culture Collection (ATCC) were used to contaminate platelets bags. The bacterially inoculated apheresis platelets were agitated at 22°C and measurements were performed using a laser instrument. Each platelet unit was measured before and during bacterial contamination. Samples were taken from each contaminated platelet bag and a standard culture plate count was used for determining bacterial concentration in the platelet medium. Using this device we have succeeded to detect bacterial concentration of above 3*106 CFU/mL staphylococcus epidermidis (Figure 1). Conclusions:Although methods to detect platelet bacterial contamination have received much attention, bacterial contamination of platelet components remains a persistent problem. The methodology described in this report detects staphylococcus epidermidis in apheresis platelet bags. The method allows for testing in real time - at issue or during storage, and it provides immediate results.This device is expected to be successful in detecting most prevalent types of bacteria strains. The test is easy to perform and does not require pre-incubation of samples or handling of the bag's contents. The device is specific and sensitive, allowing bacteria screening, ensuring increased safety of platelet transfusions. The device is able to detect bacteria in platelets, and other blood constituents, through the storage bag, without contacting, harming, or handling the bag's contents. Since there is no direct interaction of the laser light beam with the platelet media and the laser power is low (approximately 10 mW) thermal effects are avoided.By allowing real-time, sensitive detection of bacterial contamination of platelet products, wastage can be reduced, platelet shortage can be alleviated and the adverse outcomes associated with platelet transfusion contamination can be prevented. Further studies are required to evaluate the sensitivity limits for the detection of other bacterial strains that have been reported to contaminate platelet products. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

The platelet storage lesion

The continuous increase in the demand for platelet transfusion has necessitated the need to establish standards for determining the quality of platelets during storage. Bacterial contamination of platelet products and deleterious changes in structure and function referred to as the platelet storage lesion (PSL), have restricted the platelet shelf life to 5 days. The PSL and platelet health variables have been well studied and documented. The precise correlation between in vitro assays and in vivo platelet recovery and survival is yet to be established. This review presents an overview of the current understanding of PSL and the novel approaches being developed to negate the storage lesion.

A laboratory comparison of pathogen reduction technology treatment and culture of platelet products for addressing bacterial contamination concerns

Concerns over the risk of bacterial contamination of platelet products have led to implementation of bacteria culture and other screening methods. New approaches for dealing with this issue have also been proposed. A direct comparison of treatment with riboflavin and ultraviolet (UV) light (Mirasol pathogen reduction technology [PRT] system) versus bacterial culture testing (two-bottle system, 48-hour quarantine) was undertaken to compare their effectiveness. Thirteen clinically relevant bacterial organisms (20 strains) were used in this evaluation. Results were compared with spiking levels at 20 to 100 colony-forming units (CFUs) per product and at less than 20 CFUs per product. At spiking levels of 20 to 100 CFUs per product, the riboflavin and UV light process demonstrated 91% effectiveness against a broad spectrum of bacteria. In comparison, the culture method demonstrated an ability to detect up to 91% of the same contaminants, when used in the two-bottle, 48-hour-to-release configuration. At lower initial titers of contaminating agents (<20 CFUs per product), the effectiveness of PRT increased to 98% whereas the culture method effectiveness decreased to 66%. Effectiveness of the culture method further decreased to 60% when a one-bottle system was used. The results from this work suggest that the riboflavin and UV light process may provide up to 98% protection against transfusion of bacterially contaminated units at the most clinically relevant contamination levels (<20 CFUs per product). This compares favorably to the 60% to 66% effectiveness of bacterial culture testing using a 48-hour quarantine period before product release.

Isolation of Leclercia adecarboxylata from the blood culture of an asymptomatic platelet donor

Bacterial contamination of platelet (PLT) components is a leading cause of transfusion-related fatality. AABB and The College of American Pathologists require that blood centers and transfusion services have a process for detecting bacterial contamination in PLT products. Leclercia adecarboxylata was isolated from the donated blood of a healthy, asymptomatic 61-year-old man. The PLT donation was collected by apheresis method and was separated into three daughter or split products. Samples from all three products tested positive for the presence of bacterial contamination. L. adecarboxylata was subsequently identified in two of three products. The blood donor's records were reviewed and the donor was interviewed by telephone. The only possible risk identified during the interview was a questionable contact dermatitis, away from the antecubital fossa, thought to be due to poison ivy exposure before the donation. All subsequent donations have tested negative for the presence of bacterial contamination. The organism is a Gram-negative bacillus variant of the Enterobacteriaceae family and known nosocomial isolate. It has been previously reported as a rarely isolated opportunistic pathogen mostly associated with patients having compromised immunity, chronic or inflammatory illness, catheter-related bacteremia, or mixed-bacterial wounds. L. adecarboxylata was originally identified in water, foods, and environment. This is the first known report of isolation of L. adecarboxylata from the blood donation of an apparently healthy individual and could represent transient asymptomatic bacteremia or more likely contamination by epidermal flora. The organism may be underrecognized due to its close resemblance to Escherichia coli.

Development of proficiency testing for detection of bacterial contamination of platelet products

Accrediting agencies now require quality control for minimizing platelet (PLT) bacterial contamination (PBC). A proficiency testing (PT) strategy for PBC testing was developed. During Phase 1, validation of the pH meter and an enhanced bacteria detection system (Pall eBDS)--methods used in our blood bank--was accomplished with two aliquots of an apheresis PLT unit inoculated with Escherichia coli (ATCC 25922, 70 CFU/mL) or Staphylococcus aureus (ATCC 27217, 46 CFU/mL) with an uninoculated aliquot serving as a negative control. Quantitative plate culture was the reference method. PLTs were stored on a rotator at 22 degrees C. Units were sampled in duplicate at 0, 24, and 48 hours. pH testing was considered positive when the pH value was less than 6.6. eBDS was positive when the oxygen concentration was less than 9.4 percent. During Phase 2, synchronized PT of pH and eBDS was performed at four independent sites. PLT samples were inoculated and incubated as above, and aliquots were removed at Time 0 for eBDS testing and at 48 hours for pH testing. In Phase 1, on inoculated bags eBDS was positive at all time periods but pH was positive only at 48 hours. In Phase 2, synchronized results showed positive eBDS at Time 0 and positive pH at 48 hours on inoculated bags with agreement between paired sites. This strategy may serve as a useful model for developing PT materials for PBC detection. eBDS was able to identify low levels of PBC, and pH testing, only much higher levels. It is important to carefully coordinate and standardize handling of PT materials and reporting of results.

The Use of a pH Meter for Bacterial Screening of Whole Blood Platelets.

Since March 2004 the American Association of Blood Banks has required blood collection and transfusion services to have in place measures that limit and detect bacterial contamination of platelet products. At our institution we employ a pH meter to screen all whole blood platelets (WBP) at time of issue. A pH of less than 7.0 is considered a failure and the unit is quarantined and cultured. We undertook a large scale study to establish the rate of pH screening failure and rate of culture positivity of WBP. We studied a representative sample of such units for various laboratory parameters to establish the cause of the pH failure. The number of WBP subjected to pH testing between May and July 2004 was 21,751 and there were 305 failures (1.40%). The average age of the WBPs that failed pH screening was 4.6 days and the average pH was 6.57. The relationship between platelet age and rate of pH failure is shown in the Table. All WBP units that failed the pH screen were cultured; during the study period four culture-positive WBP units were identified (1.3%); in one case S. aureus was isolated from the WBP unit after 4.0 hours of culture and was also identified in the associated RBC unit after 45.6 hours. Diptheroids, coagulase negative Staphylococcus and B. subtilis were isolated from the other three culture positive WBP units however, as the accompanying RBCs remained sterile they were suspected to be contaminants. A series of 38 WBPs that failed pH testing during the study period were evaluated for platelet and WBC concentration and found to have an average WBC and PLT concentration of 2.6x103/mm3 and 1371.0x103/mm3 respectively. The WBC concentration among the WBPs that failed pH screening was more than double the concentration of the WBPs that had acceptable pH (1.2x103/mm3, p=0.005). Additionally, the units that failed pH testing contained approximately 15% more platelets than those WBP units with acceptable pH (1189.6x103/mm3, p<0.05). Our experience with pH screening of WBPs at time of issue revealed a 1.3% bacterial contamination rate of WBPs that failed pH screening. The remaining units that failed pH screening are likely attributable to significantly higher WBC and PLT concentrations. The pH screening method lacks specificity in evaluating bacterial contamination of WBPs.Relationship of WBP age and pH failureAge of WBP (days)% of total WBP issued% of pH failuresRate of pH failure by age (%)28.91.60.3316.35.60.5430.3231.1544.3702.2

Risks of blood transfusion.

To review the current status of risks of blood transfusion. English-speaking literature, literature search using key works, human data, and follow-up with key bibliographic citations. Substantial advances have been achieved in blood safety during the last 20 yrs, particularly for transfusion-transmitted viral infections. Currently, the most serious known risks from blood transfusion are administrative error (leading to ABO-incompatible blood transfusion), transfusion-related acute lung injury, and bacterial contamination in platelet products. Emerging pathogens, such as West Nile virus infection emphasize the need for implementation of proactive strategies, such as pathogen inactivation technologies, as well as reactive strategies, such as nucleic acid testing, to ensure continued advances in blood safety.

Bacterial contamination of blood components: risks, strategies, and regulation: joint ASH and AABB educational session in transfusion medicine.

Bacterial contamination of transfusion products, especially platelets, is a longstanding problem that has been partially controlled through modern phlebotomy practices, refrigeration of red cells, freezing of plasma and improved materials for transfusion product collection and storage. Bacterial contamination of platelet products has been acknowledged as the most frequent infectious risk from transfusion occurring in approximately 1 of 2000-3000 whole-blood derived, random donor platelets, and apheresis-derived, single donor platelets. In the US, bacterial contamination is considered the second most common cause of death overall from transfusion (after clerical errors) with mortality rates ranging from 1:20000 to 1:85000 donor exposures. Estimates of severe morbidity and mortality range from 100 to 150 transfused individuals each year. Concern over the magnitude and clinical relevance of this issue culminated in an open letter calling for the "blood collection community to immediately initiate a program for detecting the presence of bacteria in units of platelets." Thereafter, the American Association of Blood Banks (AABB) proposed new standards to help mitigate transfusion of units that were contaminated with bacteria. Adopted with a final implementation date of March 1, 2004, the AABB Standard reads "The blood bank or transfusion service shall have methods to limit and detect bacterial contamination in all platelet components." This Joint ASH and AABB Educational Session reviews the risks, testing strategies, and regulatory approaches regarding bacterial contamination of blood components to aid in preparing practitioners of hematology and transfusion medicine in understanding the background and clinical relevance of this clinically important issue and in considering the approaches currently available for its mitigation, as well as their implementation. In this chapter, Drs. Hillyer and Josephson review the background and significance of bacterial contamination, as well as address the definitions, conceptions and limitations of the terms risk, safe and safety. They then describe current transfusion risks including non-infectious serious hazards of transfusion, and current and emerging viral risks. In the body of the text, Dr. Blajchman reviews the prevalence of bacterial contamination in cellular blood components in detail with current references to a variety of important studies. He then describes the signs and symptoms of transfusion-associated sepsis and the sources of the bacterial contamination for cellular blood products including donor bacteremia, and contamination during whole blood collection and of the collection pack. This is followed by strategies to decrease the transfusion-associated morbidity/mortality risk of contaminated cellular blood products including improving donor skin disinfection, removal of first aliquot of donor blood, pre-transfusion detection of bacteria, reducing recipient exposure, and pathogen reduction/inactivation. In the final sections, Drs. Vostal, Epstein and Goodman describe the regulations and regulatory approaches critical to the appropriate implementation of a bacterial contamination screening and limitation program including their and/or the FDA's input on prevention of bacterial contamination, bacterial proliferation, and detection of bacteria in transfusion products. This is followed by a discussion of sampling strategy for detection of bacteria in a transfusion product, as well as the current approval process for bacterial detection devices, trials recommended under "actual clinical use" conditions, pathogen reduction technologies, and bacterial detection and the extension of platelet storage.

Liquid cold storage of platelets: A revitalized possible alternative for limiting bacterial contamination of platelet products

Liquid cold storage of platelets: A revitalized possible alternative for limiting bacterial contamination of platelet products

Liquid cold storage of platelets: A revitalized possible alternative for limiting bacterial contamination of platelet products

ACTERIAL CONTAMINATION of blood products is a recurring problem that can pose a significant risk to the transfusion recipient. With the advent of the closed system for platelet apheresis collections, the cause for concern has decreased, 1 but it has not been completely alleviated. For platelet products, bacterial contamination is especially problematic because they are stored in plasma at room temperature where bacterial pathogens can rapidly multiply to produce a significant bioburden. This was highlighted in 1986 when a group of cases of platelet transfusion-associated bacteremia was reported, and the storage period, which previously had been increased to 7 days, was reduced to 5 days to limit the time for bacterial growth in inadvertently contaminated units. 2 This has not fully eliminated the problem, and in 1990, the Food and Drug Administration received reports of six deaths as a result of bacterial sepsis; five were caused by contaminated platelets and one was caused by contaminated red blood cells) In addition, there may be the occurrence of nonfatal sepsis in as many as 1 in 1,700 transfusions of pooled platelet concentrates, 1 making platelet transfusionassociated bacteremia the most common transfusion-associated infection challenge today. 4 A simple way to decrease the growth of bacteria in stored platelets would be to store them at 4~ which retards the growth of most strains of bacteria. Although these conditions were easily adapted for storage of red blood cells, platelets were found to be significantly and irreversibly affected by exposure to cold temperatures. The coldqnduced changes negatively impact on in vivo platelet recovery and survival. It was for this reason that cold storage of platelets was abandoned. Recent

アフェレーシス血小板製剤の長期保存を目的とした閉鎖式採取回路の開発

In order to prevent bacterial contamination during the procedure of plateletapheresis, preconnected platelet rich plasma (PRP) packs were prepared which include the apheresis bowel set of a plasma collecting system (PCS) with a 16 G AVF needle and a double-or triple-bag system. The anticoagulant line of the PRP pack and that from the bag containing acid-citrate-dextrose solution formula A were welded by a sterile connection device (SCD model 312, Du Point). No additional care was needed to perform plateletapheresis with the present closed system. The 388 preparations of platelet concentrates (PCs) tested were demonstrated to be sterile. PCs stored in conventional PVC plastic bags for 3 days at room temperature were evaluated. PC5 with a plasma volume of 100ml containing 1-<2×1011 platelets stored in two 0.6 liter bags and PC10 with a plasma volume of 200-280ml containng 2-4×1011 platelets stored in two or three 1-liter PVC bags maintained their pH at the neutral level for 3 days. The percent hypotonic shock response (%HSR) of platelets was also improved during storage of 3 days. These data suggest that the present closed system will be useful for reducing the risk of bacterial contamination in platelet products during cytapheresis.