Practical Transfusion Medicine 4th Ed.

14. Bacterial contamination

Sandra Ramírez-Arcos & Mindy Goldman

Canadian Blood Services, Ottawa, Ontario, Canada

Incidence of bacterial contamination

Transfusion-associated septic events have been reduced in recent years by the introduction of several interventions including improved donor screening and skin disinfection methods, as well as implementation of first aliquot diversion and bacterial testing. However, recent reports of severe, even fatal reactions, indicate that bacterial contamination of blood components continues to be the most prevalent transfusion-associated infectious risk in Europe and North America. The UK Serious Hazard of Transfusion (SHOT) scheme documented 11 confirmed adverse transfusion reactions (ATRs) due to bacterial contamination of platelet concentrates (PCs) and red blood cells (RBCs) between 2005 and 2009, while only three possible bacterial ATRs were reported in 2010 [1,2]. From 2005 to 2010, the US Food and Drug Administration (FDA) reported 24 fatalities caused by blood components contaminated with bacteria [3]. In Canada, the Transfusion Transmitted Injuries Surveillance System Program Report for 2004–2005 described 12 serious ATRs with eight of the cases relating to contaminated RBCs [4]. Since 2004, Canadian Blood Services has received six reports of ATRs due to bacterial contamination of blood components including PCs and RBCs (personal communication).

The current incidence of bacterial contamination in PCs varies from 1/1000 to 1/5000, with an estimated risk of transfusion-transmitted septic reactions of 1/100 000 and a fatality rate of 1/million [5,6], while the prevalence of bacterially contaminated RBCs is 1/30 000 with a septic reaction rate of 1/500 000 and a fatality rate of 1/10 million [7].

Blood components implicated in adverse transfusion reactions

Platelet concentrates

Platelet concentrates are the blood components most susceptible to bacterial contamination due to their storage conditions. PCs are stored with constant agitation at 22 ± 2°C in oxygen-permeable plastic containers. The anticoagulant solutions added during PC production provide a physiological pH and a glucose content of 500 mg/dL. All of these conditions offer an ideal environment for bacterial growth. The initial levels of bacteria in PCs are usually exceedingly low (<10 colony forming units, CFU) but clinically significant levels (105 CFU/ml) can be reached after 3–5 days of storage depending on the organism [5,8,9].

Clinical sequelae of transfusing bacterially contaminated PCs are variable and may be acute or delayed, depending on the severity of the recipient's medical condition, the type and concentration of the contaminant organism and the timing of transfusion. It is accepted that sepsis due to bacterial contamination of PCs is underrecognized and patients developing severe or fatal infections are more likely to be diagnosed and reported [5,8].

Red blood cells

Storage of RBC units at low temperatures (1–6°C) is believed to limit bacterial growth and decrease the risk of adverse posttransfusion events. However, psychrophilic (grow optimally at refrigeration temperatures) pathogenic bacteria can proliferate from very low levels of contamination to clinically significant concentrations under RBC storage conditions.

Reactions associated with transfusion of bacterially contaminated RBC units are usually severe, due to infused endotoxin (lipopolysaccharide) associated with the cell wall of Gram-negative bacteria. Clinical symptoms may include fever over 38.5°C, hypotension, nausea and vomiting starting during the transfusion. Septic shock with complications such as oliguria and disseminated intravascular coagulation may occur [7,8].

Plasma and cryoprecipitate

The incidence of ATRs due to contaminated plasma or cryoprecipitate is very low. Only a few reports are found in the literature documenting cases of products being contaminated during thawing in waterbaths. Recipients developed severe infections including endocarditis and septicaemia several days posttransfusion [80].

Contaminant bacterial species

Platelet concentrates

Gram-positive bacteria are the predominant PC contaminants. Although these bacteria have the ability to survive and proliferate during PC storage, most of them are considered to be nonpathogenic. Coagulase negative staphylococci and propionibacteria are the predominant bacterial contaminants of PCs with Staphylococcus epidermidis being the species most commonly isolated [5,10]. Transfusions with fatal outcomes due to platelets contaminated with Staphylococcus epidermidis have been reported in Canada, the USA and Europe [8]. Missed detection of Staphylococcus epidermidis is attributed to low initial concentration, its characteristic slow growth under platelet storage conditions and the ability of some strains to form slimy bacterial aggregates attached to the platelet containers known as biofilms [8,11]. Other Gram-positive bacteria often identified as PC contaminants include corynebacteria, Staphylococcus aureusBacillus spp. and Streptococcus spp. [5,8,10]. Most of the PC contaminants are either aerobic or facultative anaerobic bacteria; however, there have been reports of septic reactions associated with strict anaerobic organisms such as Clostridium perfringens [10]. The anaerobe Propionibacterium acnes is a common platelet contaminant and, although mild transfusion reactions with this organism have been reported, its clinical relevance in transfusion settings is still under debate [10].

Although less commonly recognized as PC contaminants, Gram-negative bacteria can be present and will cause severe and often fatal infections due to the potent septic shock reaction induced by the endotoxin, which elicits an uncontrolled inflammatory response in the recipient. The most frequently identified Gram-negative PC contaminants include Escherichia coliKlebsiella pneumoniaeEnterobacter spp. and Serratia spp. [6,8–10].

Red blood cells

RBCs are the most frequently transfused blood component. The predominant RBC contaminants are Gram-negative bacteria of the family Enterobacteriacea, with Yersinia enterocolitica being the predominant species. Recovering donors who had Yersinia enterocolitica infections can be asymptomatic due to the low bacterial content in their bloodstream (<10 CFU/ml). Yersinia growth in RBCs is supported by the storage conditions; being a psychrophilic organism, this bacterium proliferates well at 1–6°C, reaching concentrations >108 CFU/ml after 3 weeks of incubation. Yersinia enterocolitica lacks siderophores for iron acquisition, which results in a long lag phase (from 1 to 3 weeks) until free haemin is available from spontaneous RBC haemolysis. Glucose and adenine, used as energy sources by this organism, are provided by the RBC anticoagulant solutions. Transfusion of RBC units heavily contaminated with Y. enterocolitica results in severe septic shock due to high levels of endotoxin [12].

Other RBC Gram-negative bacterial contaminants include Serratia spp., Pseudomonas spp., Enterobacter spp., Campylobacter spp. and Escherichia coli, all of which have the potential to cause endotoxic shock in recipients [6,8,9,10].

Plasma and cryoprecipitate

Burkolderia cepacia (previously known as Pseudomonas cepacia) and Pseudomonas aeruginosa have been implicated in ATRs due to contaminated plasma and cryoprecipitate [8].

Sources of contamination

Contaminant bacteria of blood components can originate from the donor or the blood collection and processing procedures (Table 14.1).

Table 14.1 Sources of bacterial contamination and prevention strategies. Reproduced from Ramirez-Arcos S, Goldman M & Blajchman MA. Bacterial contamination. In: MA Popovsky (ed.), Transfusion Reactions. Bethesda, MD: American Association of Blood Banks; 2007, pp. 163–206 [8].

Source of contamination

Possible control measures

Blood donor

·        Silent bacteraemia

·        Respiratory flora

·        Donor screening

·        Pretransfusion detection

·        Pathogen reduction technologies

Blood collection procedures

·        Normal and transient skin flora

·        Collection practices and equipment

·        Skin disinfection

·        First aliquot diversion

·        Pretransfusion detection

·        Pathogen reduction technologies

Blood processing procedures

·        Improved quality control

·        Pretransfusion detection

·        Pathogen reduction technologies

Blood donor

The predominant blood component bacterial contaminants are aerobic and anaerobic Gram-positive bacteria that are part of the normal skin flora and, more rarely, Gram-negative bacteria that can originate from silent donor bacteremia or be part of the transient skin flora. It is impossible to completely decontaminate human skin and it has been reported that normal skin flora organisms such as Staphylococcus epidermidis can adhere firmly to human hair despite skin disinfection [5,6,8–10].

Different bacteria can be part of the transient skin flora. Clostridium perfringens, which is part of faecal flora, was implicated in a fatal ATR. The microorganism was isolated from the arm of a donor who frequently changed his children's diapers. A Salmonella enterica isolate, which caused two transfusion-associated sepsis events, was found in a stool sample of the pet boa owned by the donor implicated in this case. Although not confirmed, it was speculated that the bacterium was present on the donor's skin at the time of donation [8].

On the odd occasion, asymptomatic donor bacteraemia may lead to contamination of blood components. Low level bacteraemia may occur in the incubation or recovery phase of acute infections after procedures such as tooth extraction. Chronic, low grade infections, such as osteomyelitis, have been associated with contaminated platelet products, as have gastrointestinal disorders such as diverticulosis and colon cancer [13].

Blood collection and production processes

Blood collection and production processes can also be sources of bacterial contamination. Three cases of Serratia marcescens sepsis following platelet transfusions were linked to contaminated vacuum tubes used for blood collection [8]. Burkolderia cepacia and Pseudomonas aeruginosa implicated in ATRs due to contaminated plasma and cryoprecipitate were isolated from the waterbaths used to thaw the products [8].

Although rare, unusual practices during blood collection could also result in blood component contamination. A cool cloth contaminated with Pseudomonas fluorescens, which was used by a donor with low pain tolerance, led to heavy contamination of an RBC unit that was transfused, causing a severe transfusion reaction [8].

Investigation of transfusion reactions (also see Chapter 6)

Symptoms of transfusion-associated septic reactions usually appear during the first four hours after the transfusion was initiated. If a septic reaction is suspected, the transfusion should be stopped immediately and the open port of the blood component must be covered immediately to avoid environmental contamination. Remaining component, intravenous solutions and blood samples from the recipient should be sent to a microbiology laboratory for investigation. Septic transfusion reactions are confirmed if the same bacterium is isolated from the recipient and the implicated blood component. Associated components to the concerned blood component should be recalled, and if available, also cultured. If the contaminant organism is not part of the normal skin flora, the donor should be contacted and followed up. Donor deferral might be necessary but it should be based on medical judgement depending on the laboratory results and the microorganism identified [13].

Donors with silent bacteraemia identified during routine platelet screening should also be investigated. The donor's health should be considered as well as the possibility of recurrent contaminated donations. Depending on the results of the investigation, donor deferral from future donations might be required [14].

Prevention strategies

Strategies used to decrease the levels of bacterial contamination in blood components include donor screening, skin disinfection, first aliquot diversion, pretransfusion detection and pathogen reduction technologies (Table 14.1).

Donor screening

Most transfusion centres have established methods for donor screening to avoid collection of potentially contaminated blood components. Donor screening includes body temperature determination and answering a questionnaire that includes questions related to the donor's general health and potential signs of infection or silent bacteraemia, such as the occurrence of recent dental work, gastrointestinal diseases or malaise.

Skin disinfection

Since the majority of bacteria found in contaminated blood components are part of the skin flora, optimal skin disinfection of the phlebotomy site is essential to maximize the inactivation of contaminant bacteria during blood donation.

Several factors affect the efficacy of skin disinfection including: the type and concentration of antiseptic used, the mode of application (scrub, swab, applicator or ampoule), whether there is a single or two-step method, the time that the antiseptic is in contact with the skin and the training of the personnel applying the disinfectant. A two-step method involving a scrub with a 0.75% povidone–iodine compound followed by an application of a 10% povidone–iodine preparation solution is recommended by the AABB. For donors sensitive to iodine, the use of 2% chlorhexidine and 70% isopropyl alcohol is optional and, for donors that react to both iodine and chlorhexidine, using only isopropyl alcohol should be considered. Currently, a one-step 2% chlorhexidine and 70% isopropyl alcohol skin cleansing kit is being used in the UK, the USA, Australia and Canada. The Australian Red Cross reported a 99% reduction in bacterial load after implementing the use of a one-step swab containing a chlorhexidine–alcohol antiseptic. Similarly, rate reductions have been observed in the UK and the USA upon implementation of the enhanced method [5,8].

First aliquot diversion

Diversion of the first 30–40 ml of blood at the point of collection has been associated with significant reduction in contamination by skin flora. The diverted blood sample is either discarded or used for viral and immunohaematology testing. Significant reductions of the whole blood bacterial contamination rate as a result of the implementation of a diversion bag have been reported by the Sanquin Blood Blank, the Québec Hemovigilance System, the American Red Cross and the Japanase Red Cross [6,8,15].

Single donor apheresis versus pooled platelet concentrates

An increased risk of bacterial contamination has been traditionally associated with pooled PCs in comparison to single donor apheresis PCs due to a potential pooling of microorganisms [6]. However, nowadays apheresis donors may donate by a double or triple platepheresis procedure and therefore multiple contaminated therapeutic units can be produced, counterbalancing the ‘pooling’ effect of whole-blood-derived PCs. Studies from other countries such as Canada and Germany have shown that the rate of contamination of apheresis PCs and buffy coat platelet pools is similar [16,17].

Bacterial detection methods

Routine testing for bacterial contamination has been implemented in several countries to screen apheresis and whole-blood-derived PCs. RBCs or plasma are not tested for bacterial contamination; however, RBC and/or plasma units associated with contaminated whole-blood-derived PCs are removed from the inventory, if available. There is evidence that only 40% of RBC and plasma units associated with bacterially contaminated PCs would test positive [8].

Detection of bacteria in transfusable blood components is more complex than viral detection since bacterial concentrations increase over time under routine blood component storage conditions. Factors that should be considered prior to the implementation of a bacterial screening method include: the time of testing, the method used for sample collection, the sample volume to be tested, the time required to perform the test and whether the blood component should be quarantined prior to testing. Since initial bacterial loads are usually very low (<1 CFU/mL), a very sensitive technique should be used in the blood collection centre shortly after collection. However, less sensitive methods may be used at the hospital end for blood component screening prior to transfusion.

Pretransfusion detection methods used by blood component suppliers

The BacT/ALERT® 3D system (bioMérieux, Marcy l'Etoile, France) and the Pall enhanced Bacterial Detection System (eBDS, Pall Corporation, New York, USA) are culture systems that have been licensed in Europe and North America to detect bacterial contamination in PCs [5,6,8].

The BacT/ALERT System uses liquid aerobic and anaerobic culture bottles with a colorimetric sensor at the bottom that changes colour from green to yellow when pH decreases as a result of the metabolic activity of growing bacteria. The culture bottles are inoculated with 8–10 mL of PC samples and are incubated at 36°C for one to six or seven days depending on the centre. It is reported that this system can detect 1–10 CFU/mL of most common platelet contaminants. The BacT/ALERT system has been widely used for bacterial testing of apheresis and whole-blood-derived PCs. When an initial positive culture is confirmed by repeat testing of the implicated blood component, a retention sample and/or samples from the recipient, it is considered to be a true (confirmed) positive. Table 14.2 summarizes the rate of contamination in selected blood centres that use the BacT/ALERT system for platelet screening. True positive rates vary from 1/134 to 1/7 536 (Table 14.2).

Table 14.2 Prevalence of bacterial contamination in platelet concentrates in selected blood centres.

Table014-1

Despite its high sensitivity, several reports of missed bacteria detection in apheresis and whole-blood-derived PCs tested by the BacT/ALERT system have been reported worldwide. Examples of microorganisms that were implicated in false negative cases include: Salmonella, Serratia marcescens, Group A StreptococcusStaphylococcus aureus and coagulase negative Staphylococcus in Canada [16] and Staphylococcus aureus, coagulase negative staphylococci, Streptococcus spp., Serratia marcescens, Escherichia coli, Klebsiella oxytocaMorganella morgannii (previously known as Proteuns morganii) and the anaerobe Eubacterium limosum in the USA [3]. All of these false negatives resulted in severe or fatal reactions. It is likely that many false negative results were not recognized because no reactions occurred or signs and symptoms of a reaction were mild. Attempts to decrease the likelihood of false negative cultures include the use of a two-bottle (aerobic and anaerobic) culture system and/or retesting components after 3–4 days of storage.

Most centres are routinely testing for aerobic bacteria, as the majority of clinically significant organisms belong to this group. Centres using the two-bottle system have reported an increase in the detection rate of bacterial contamination in PCs since anaerobic culture bottles allow the capture of strict anaerobic bacteria such as Propionibacterium acnes and Staphylococcus saccharolyticus. Although cases of transfusion-transmitted Propionibacterium acnes have been reported, none of them have resulted in severe transfusion reactions. However, there are reports of severe and fatal ATRs due to the presence of the anaerobes Eubacterium limosum and Clostridium perfringens. It has also been documented that some platelet contaminants including Staphylococcus spp. and Serratia marcescens can be preferentially recovered from anaerobic culture media and not from aerobic cultures. Implementation of anaerobic bacterial cultures is still controversial due to the doubtful clinical relevance of Propionibacterium acnes, the most common anaerobic platelet contaminant, and the high incidence of false positive results obtained with anaerobic culture bottles [3,5,8,10].

The Pall Bacterial Detection System uses the decrease in oxygen concentration as an indicator of bacterial growth in PCs. Between 4 and 6 mL of PC samples are transferred into an incubation bag. After 24–30 hours of incubation, the oxygen concentration of this bag is measured with an oxygen analyser. A decrease in the percentage of oxygen to ≤19.5% is indicative of bacterial growth. This system only detects aerobic Gram-positive and Gram-negative bacteria at the levels of 100–500 CFU/mL with a sensitivity of 96.5%. The Pall eBDS system has been validated for bacteria detection in both leucocyte-reduced PCs and RBCs [5,6,8].

Other methods developed to detect bacterial contamination in PCs include detection of bacterial 16S rRNA genes by reverse transcriptase polymerase chain reaction and pH monitoring [6,8]. However, these methods are neither sensitive nor specific enough to be an alternative for the automated culture-base methods currently used by the blood production centres.

Bacterial detection methods to be used prior to transfusion

Methods to be used at the hospital end can be less sensitive detecting bacteria in the range of 103–104 CFU/mL, but such tests need to be rapid and specific. The new AABB Interim Standard 5.1.5.1.1 requests the use of methods that have been either validated or approved by the Food and Drug Administration (FDA). Therefore, subjective, nonsensitive and/or complex and time-consuming methods such as visual examination, staining of platelet smears and multireagent strip testing are no longer recommended in the US.

The easy-to-use rapid immunoassay Verax PGD test has been licensed by the FDA as a point-of-use assay for bacterial detection in apheresis and whole-blood-derived PCs that have been previously tested with an approved culture-based test. The PGD assay can detect aerobic and anaerobic bacteria based on the existence of conserved bacterial cell wall antigens. The test has a sensitivity of 8.2 × 103 to 8.6 × 105 CFU/mL depending on the contaminant microorganism and a specificity of 98.4–99.7% depending on the platelet type. Recent studies showed that the PGD test detected contaminated PCs that had been released as negative by initial screening with automated culture systems, demonstrating the utility of this assay as a point of release test [18].

Pathogen reduction technologies

In contrast to testing, pathogen reduction technologies (PRT) involve the treatment of PCs as soon as possible after collection with a process to inactivate or reduce the level of contaminating bacteria, viruses, parasites and residual leucocytes. Two technologies, Mirasol® (TerumoBCT, CO, USA) and INTERCEPT Blood System (Cerus Europe BV, Amersfoort, The Netherlands) have received CE (Conformité Européenne) Mark registration and have been introduced into routine use by several European countries. Neither of these technologies has been licensed in North America. Both of these processes utilize photochemical techniques with different mechanisms of action. A third technology, THERAFLEX UV Platelets technology, which utilizes UVC light without a photochemical compound, is in clinical development and has not been introduced into routine use [5].

The INTERCEPT process is used within the first 24 hours after collection and utilizes a synthetic psoralen, amotoslaen HCl, which targets nucleic acid and utilizes UVA light (3 J/cm2: 320–400 nm) to form covalent adducts with nucleic acids. INTERCEPT inactivates a broad spectrum of Gram-positive and Gram-negative bacterial species associated with ATRs but cannot inactivate bacterial spores. In countries where the system has been used for several years, no ATRs related to bacterial contamination have been reported [5].

The Mirasol® system uses riboflavin (vitamin B2, 50 μg per 300 ml) with UVC, UVB and a portion of UVA light (265–375 nm). The efficacy of this process is based on the association of riboflavin with nucleic acids and the generation of reactive oxygen species, leading to nucleic acid disruption rather than adduct formation. In a spiking study, the efficacy of Mirasol to inactivate Gram-positive and Gram-negative bacteria ranged from 33 to 100% but not all bacterial strains were completely inactivated; no data have been reported regarding bacterial spore destruction [5].

Key points

1. Bacterial contamination of blood components poses the most prevalent transfusion-transmitted infectious risk.

2. Platelet concentrates are the blood components most susceptible to bacterial contamination due to their storage conditions.

3. Interventions such as improved donor screening and skin disinfection, first aliquot diversion and bacterial testing have decreased the occurrence of transfusion-associated septic events.

4. Gram-positive skin flora are the predominant blood component contaminants.

5. Gram-negative bacteria originated from silent donor bacteraemia or transient skin colonization, are less frequently found as blood component contaminants, but they pose the major infectious risk due to their production of endotoxin.

6. Platelet concentrates are the only blood component that is routinely tested for bacterial contamination.

7. The BacT/ALERT and Pall eBDS automated culture systems are the only methods currently licensed for routine testing of platelet concentrates by blood component suppliers in Europe and North America.

8. Recommended bacterial detection methods to be used prior to transfusion at the hospital end include repeat culture and the new immunoassay PGD test.

9. Despite high sensitivity of the current testing methods, contaminated PC units still escape detection, resulting in false negative transfusion cases.

10. Pathogen reduction technologies are the ultimate approach to prevent bacterial contamination of blood components.

References

1. Serious Hazards of Transfusion SHOT. Summary of Annual Report 2009 [homepage on the Internet]. Available from: http://www.shotuk.org/shot-reports/report-and-summary-2009/ (last accessed 6 October 2011).

2. Serious Hazards of Transfusion (SHOT). Summary of Annual Report 2010 [homepage on the Internet]. Available from: http://www.shotuk.org/shot-reports/report-and-summary-2010-2/ (last accessed 6 October 2011).

3. Fatalities Reported to FDA Following Blood Collection and Transfusion. Annual Summary for Fiscal Year 2010 [homepage on the Internet]. Available from: http://www.fda.gov/downloads/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/TransfusionDonationFatalities/UCM254860.pdf (last accessed 6 October 2011).

4. Transfusion Transmitted Injuries Surveillance System Program Report 2004–2005 [homepage on the Internet]. Available from: http://www.phac-aspc.gc.ca/hcai-iamss/tti-it/pr-re0405/pdf/ttiss-ssit0405-eng.pdf. (last accessed 6 October 2011).

5. Corash L. Bacterial contamination of platelet components: potential solutions to prevent transfusion-related sepsis. Expert Rev Hematol 2011; 4(5): 509–525.

6. Palavecino EL, Yomtovian RA & Jacobs MR. Bacterial contamination of platelets. Transfus Apher Sci 2010; 42(1): 71–82.

7. Chen CL, Yu JC, Holme S, Jacobs MR, Yomtovian R & McDonald CP. Detection of bacteria in stored red cell products using a culture-based bacterial detection system. Transfusion 2008; 48(8): 1550–1557.

8. Ramirez-Arcos S, Goldman M & Blajchman MA. Bacterial contamination. In MA Popovsky (ed.), Transfusion Reactions. Bethesda, MD: American Association of Blood Banks (AABB), 2007, pp. 163–206.

9. Jacobs MR, Good CE, Lazarus HM & Yomtovian RA. Relationship between bacterial load, species virulence, and transfusion reaction with transfusion of bacterially contaminated platelets. Clin Infect Dis 2008; 46(8): 1214–1220.

10. Walther-Wenke G, Schrezenmeier H, Deitenbeck R, Geis G, Burkhart J, Höchsmann B et al. Screening of platelet concentrates for bacterial contamination: spectrum of bacteria detected, proportion of transfused units, and clinical follow-up. Ann Hematol 2009; 89: 83–91.

11. Greco C, Martincic I, Gusinjac A, Kalab M, Yang AF & Ramírez-Arcos S. Staphylococcus epidermidis forms biofilms under simulated platelet storage conditions. Transfusion 2007; 47(7): 1143–1153.

12. Guinet F, Carniel E & Leclercq A. Transfusion-transmitted Yersinia enterocolitica sepsis. Clin Infect Dis 2011; 53(6): 583–591.

13. Public Health Agency of Canada. Guideline for Investigation of Suspected Transmitted Bacterial Contamination [homepage on the Internet]. Available from: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08vol34/34s1/34s1-eng.php (last accessed 6 October 2011).

14. Eder AF & Goldman M. How do I investigate septic transfusion reactions and blood donors with culture-positive platelet donations? Transfusion 2011; 51(8): 1662–1668.

15. Robillard P, Delage G, Itaj NK & Goldman M. Use of hemovigilance data to evaluate the effectiveness of diversion and bacterial detection. Transfusion 2011; 51(7): 1405–1411.

16. Jenkins C, Ramírez-Arcos S, Goldman M & Devine DV. Bacterial contamination in platelets: incremental improvements drive down but do not eliminate risk. Transfusion 2011; 51(12): 2555–2565.

17. Schrezenmeier H, Walther-Wenke G, Müller TH, Weinauer F, Younis A, Holland-Letz T et al. Bacterial contamination of platelet concentrates: results of a prospective multicenter study comparing pooled whole blood-derived platelets and apheresis platelets. Transfusion 2007; 47(4): 644–652.

18. Jacobs MR, Smith D, Heaton WA, Zantek ND & Good CE; PGD Study Group. Detection of bacterial contamination in prestorage culture-negative apheresis platelets on day of issue with the PAN Genera Detection test. Transfusion 2011; 51(12): 2573–2582.

19. Eder AF, Kennedy JM, Dy BA, Notari EP, Skeate R, Bachowski G et al. Limiting and detecting bacterial contamination of apheresis platelets: inlet-line diversion and increased culture volume improve component safety. Transfusion 2009; 49(8): 1554–1563.

20. Pearce S, Rowe GP & Field SP. Screening of platelets for bacterial contamination at the Welsh Blood Service. Transfus Med 2011; 21(1): 25–32.

Further reading

AABB Association Bulletin #04-07. Actions Following an Initial Positive Test for Possible Bacterial Contamination of a Platelet Unit [homepage on the Internet]. Available from: http://www.aabb.org/resources/publications/bulletins/Pages/ab04-07.aspx (last accessed 7 October 2011).

AABB Association Bulletin #05-02. Guidance on Management of Blood and Platelet Donors with Positive or Abnormal Results on Bacterial Contamination Tests [homepage on the Internet]. Available from: http://www.aabb.org/Content/Members_Area/Association_Bulletins/ab05-2.htm (last accessed 7 October 2011).

AABB Association Bulletin #10-05. Suggested Options for Transfusion Services and Blood Collectors to Facilitate Implementation of BB/TS Interim Standard 5.1.5.1.1 [homepage on the Internet]. Available from: http://www.aabb.org/resources/publications/bulletins/Pages/ab05-02.aspx (last accessed 7 October 2011).

AuBuchon & Prowse CV (eds). Pathogen Inactivation. The Penultimate Paradigm Shift. Bethesda, MD: AABB Press; 2010.

Blajchman MA, Beckers EAM, Dickmeiss E, Lin L, Moore G & Muylle L. Bacterial detection of platelets: current problems and possible resolutions. Transfus Med Rev 2005; 19: 259–272.

Brecher ME & Hay SN. Bacterial contamination of blood components. Clin Microbiol Rev 2005; 18: 195–204.

Dumont LJ, Kleinman S & Murphy JR. Screening of single-donor apheresis platelets for bacterial contamination: the PASSPORT study results. Transfusion 2010; 50: 589–599.

INTERCEPT Blood System by Cerus Corporation [homepage on the Internet]. Available from: http://www.interceptbloodsystem.com/ (last accessed 6 October 2011).

Mirasol® Pathogen Reduction Technology [homepage on the Internet]. Available from: http://www.caridianbct.com/location/emea/products-and-services/Pages/mirasol-pathogen-reduction-technology.aspx (last accessed 6 October 2011).

Platelet PGD test http://www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts/approvedproducts/substantiallyequivalent510kdeviceinformation/ucm190504.pdf (last accessed 7 October 2011).



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