Dr Anand Deshpande P D Hinduja National Hospital & MRC Mumbai

 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

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

“SHOT” DATA

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.

CAP CHECKLIST – TRM – 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.

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

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

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

Transfusion fatalities by organisms in Red cell transfusions (25)

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

Organisms in Platelet component  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

Plasma / Cryo  Frozen state  Rarely associated with contamination

Strategies to reduce risk of post transfusion sepsis BBacterial Avoidance GGrowth inhibition DDetection EElimination

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

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

Percentage of Donors with Bacteria growth after skin disinfection

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

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

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

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

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

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

 Bacterial genome detection – NAT  Bacterial culture – most reliable method – 24 hrs

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

V. Pathogen inactivation  Final common pathway  Photodynamic and photochemical methods

UK experience - Poster at Cancun – ISBT  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

Factors affecting outcome of Transfusion of Bacterially contaminated blood components

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

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 ……………

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……………….