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Dr Anand Deshpande P D Hinduja National Hospital & MRC Mumbai

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While the blood bank community has successfully implemented the high standards of blood screening for viral markers including NAT screening, transmission of donor bacteria has clearly emerged as the greatest infectious risk to transfusion safety Bacterial contamination of blood products is a persistent but often overlooked problem in Transfusion Medicine

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The dramatic decrease in risk of transfusion-transmitted viral disease was accomplished by conversion from Paid to volunteer whole blood donors in the 1970s. Increased direct questioning of donors regarding risks for the Viruses and increased testing of collected donor blood for antibodies, antigens and nucleic acid of these viruses starting in the 1970s. Risk of hepatitis B may decrease further with universal childhood vaccination. Not shown in the graph are the rare risks of other transmissible diseases. The dashed line indicates the unknown risks, if any, of new viruses and other potentially emerging pathogens, such as prions that cause new variant Creutzfeldt-Jakob Disease. (J of Am Med Ass, Feb 2001, Volume 285, No 5; 579

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SHOT DATA

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CAP CHECKLIST TRM.44955PHASE II Does the laboratory have a validated system to detect the presence of bacteria in platelet concentrates ? For random donor platelets, any of the following testing methods satisfy this checklist question: detection of decreased pH or glucose by analytic instrument or dipstick; gram stain; acridine orange stain. Though of low sensitivity, these methods may detect units that are heavily contaminated by bacteria. Culture or FDA- approved commercial detection systems have greater sensitivity. The swirling technique is not recommended because of its very low sensitivity.

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CAP CHECKLIST TRM.44955 Revised (Nov 2011)PHASE II Bacterial Contamination in Platelets The enhanced sensitivity requirement reflects the availability of multiple FDA-cleared quality control strategies; insensitive methods including pH, glucose and microscopy are no longer acceptable. Equivalent system is defined as a system that has been validated to demonstrate comparable or improved sensitivity in CFU/mL. If this testing is performed by the supplier of platelet components, the laboratory can satisfy this checklist requirement by having an agreement with the supplier to be notified of supply units suspected of containing bacteria.

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Origin of bacteria From donor Unsuspected bacterimia Venipuncture site Rarely during processing and storage At the time of transfusion

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Risk estimates HIV / HCV / HAV 1 in a few million HBV 1 in 0.3 million Bacteria (RBCs) 1 in 30,000 Bacteria (Platelets) 1 in 3000

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Organisms in RBC component Yersinia entercolotica, Serratia & Pseudomonas Y. enterocolitis fever, diarrhea Endotoxins Initial lag phase rapidly proliferative after 20 25 days of storage 25 fatalities reported in USA (1995 2004) Risk of death 0.13 / million Autologous

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Transfusion fatalities by organisms in Red cell transfusions (25)

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Summary of Organisms from RBC Transfusions identified in the BACON, SHOT and BACTHEM studies

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Organisms in Platelet component 50 -250 times higher risk than viral infection Room temperature storage Organisms are varied coagulase negative staphylococcus commonest, Bacillus Contamination risk is 1:3000 approx, whereas Septic reactions occur in 1/4 th to 1/6 th of the contaminated platelets Fatalities gram negative organisms Clinically, Fever-Hypertension-Sepsis-Death Sometimes difficult to diagnose

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Plasma / Cryo Frozen state Rarely associated with contamination

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Strategies to reduce risk of post transfusion sepsis BBacterial Avoidance GGrowth inhibition DDetection EElimination

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I. Bacterial Avoidance A] Donor screening Careful selection of healthy blood donors Recent dental procedures Recent use of antibiotics/Medical & surgical interventions Problems e.g. Yersinia sepsis retrospective analysis 50 % donors had GI symptoms Special considerations Autologous blood units

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Bacterial avoidance B] Skin preparations Not possible to have sterile venipuncture Sebaceous glands / Hair follicles Scarring or dimpling Isopropyl alcohol + Iodine + Isopropyl alcohol Chlorhexidine

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Percentage of Donors with Bacteria growth after skin disinfection

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Bacterial avoidance C] Diversion Significant reduction in blood contamination if first 10 -20 ml of blood is diverted to the pouch Study from Netherlands 0.35 % - 0.21 % Expected to reduce gram positive organisms

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Apheresis vs WBD platelets Significant reduction in sepsis (John Hopkins study) 1:4818 1: 15098 Cultures with apheresis platelets

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II. Growth inhibitors Optimising storage temperature Red cells (1 0 6 0 C) Yersinia / Serratia Frozen - ? Practicality Platelets (20 0 24 0 C) 4 0 C Temperature induced activation

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Growth inhibition Optimising storage time A. Red Cells Yersinia sepsis in units > 25 days old Proposed to reduce shelf life for 25 days Rejected 20 % units > 25 days - Recruiting new donor - Units < 25 days also causes sepsis

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B. Platelets Ideal would be 1 2 days Diagnostic disease markers impossible (NAT/Culture)

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III. Bacterial detection No ideal procedure for detection of bacteria Limitations Short shelf life of 5 days The amount of bacterimia changes with time Contamination may occur during sampling processes Innoculation may be very small

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Bacterial genome detection NAT Bacterial culture most reliable method 24 hrs

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IV. Bacterial elimination Leucodepletion by filtration Prestorage leucocyte filters Related to leucocyte phagocytosis Related to direct filter binding mechanism No evidence that prestorage leucocyte reduction by filtration contributed to bacterial proliferation

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V. Pathogen inactivation Final common pathway Photodynamic and photochemical methods

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UK experience - Poster at Cancun ISBT - 2012 1996 2010 40 cases SHOT 33/40 platelet transfusion 9/33 fatalities NHS BacT / ALERT for culture 0.03% confirmed positive No report of transmission of bacteria by transfusion of platelets in 2011

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Factors affecting outcome of Transfusion of Bacterially contaminated blood components

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Under reporting Septic or fatal reaction elderly, neonates or patients immunocompromised by illness or chemo If patients on antimicrobial therapy - severity Low levels of bacterial contamination causes mild symptoms like fever and chills resembling FNHTRs

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Conclusion . Significant progress in understanding Source reduction by good skin preparation and diversion pouch Better and specific method like Bact culture Towards safer blood and better patient care

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Conclusion There is always another pathogen waiting its turn A zero-risk blood supply is not achievable The safest transfusion is still the one not infused.

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