Bacterial testing of platelets - has it prevented transfusion-transmitted bacterial infections in Australia?

BACKGROUND AND OBJECTIVES: Australia introduced bacterial contamination screening (BCS) for platelet components in April 2008. This study presents analysis performed to assess the efficacy of testing. MATERIALS AND METHODS: Seven-day aerobic and anaerobic culture is performed using the BacT/ALERT 3D system. Following an initial machine positive (IMP) flag, all associated components are recalled, and/or clinicians treating already transfused patients are notified. IMPs are categorized as 'machine false positive', 'confirmed positive' or 'indeterminate' depending on culture results of initial and repeat samples. RESULTS: Between 2010 and 2012, 1·1% of platelet donations tested IMP; since 2013, this rate has fallen to 0·6% through improved instrument management, reducing false-positive IMPs but maintaining sensitivity for cultures yielding bacterial growth. On average, 66% of confirmed positive and indeterminate platelet units had been transfused at the time of detection. The majority (95%) of these grew Propionibacterium sp., a slow-growing organism that rarely causes sepsis in the transfusion setting. The incidence of reported transfuion-transmitted bacterial infection (TTBI) has fallen since the introduction of BCS, with a 4·2-fold [0·5, 28·2] lower rate from platelets. CONCLUSION: BCS has been successful in detecting platelet units containing pathogenic bacteria. The incidence of TTBI from platelets has fallen since the introduction of BCS, but the risk has not been eliminated due to rare false-negative results. In the absence of a pathogen inactivation system for red blood cells, BCS provides 'surrogate' testing of red blood cells from which platelets have been manufactured.

Business continuity in blood services: two case studies from events with potentially catastrophic effect on the national provision of blood components.

BACKGROUND AND OBJECTIVES: NHS Blood and Transplant (NHSBT) and the Australian Red Cross Blood Service (ARCBS) are national blood establishments providing blood components to England and North Wales, and Australia, respectively. In 2012, both services experienced potentially catastrophic challenges to key assets. NHSBT suffered a flood that closed the largest blood-manufacturing centre in Europe, whilst ARCBS experienced the failure of a data centre network switch that rendered the national blood management system inaccessible for 42 h. This paper describes both crisis events, including the immediate actions, recovery procedures and lessons learned. MATERIALS AND METHODS: Both incidents triggered emergency response plans. These included hospital reprovisioning and recovery from the incident. Once normal services had been restored, both events were subjected to root cause analysis (RCA) and production of 'lessons learned' reports. RESULTS: In both scenarios, the key enablers of rapid recovery were established emergency plans, clear leadership and the support of a flexible workforce. Product issues to hospitals were unaffected, and there were no abnormal trends in hospital complaints. RCA identified the importance of risk mitigations that require co-operation with external organizations. Reviews of both events identified opportunities to enhance business resilience through prior identification of external risks and improvements to contingency plans, for example by implementing mass messaging to staff and other stakeholders. CONCLUSIONS: Blood establishment emergency plans tend to focus on responding to mass casualty events. However, consolidation of manufacturing to fewer sites combined with a reliance on national IT systems increases the impact of loss of function. Blood services should develop business continuity plans which include prevention of such losses, and the maintenance of services and disaster recovery.

Assessing the safety and efficacy of a test-based, targeted donor screening strategy to minimize transfusion transmitted malaria.

BACKGROUND AND OBJECTIVES: In 2005, the Australian Red Cross Blood Service implemented a malaria antibody testing based strategy for donors with a history of travel/residence in a malaria endemic country or a past history of malaria. This report assesses the safety and efficacy of the strategy since inception. MATERIALS AND METHODS: Eligible blood donors were tested using the Newmarket malarial antibody EIA at least 4 months after their last potential exposure. Where EIA non-reactive their quarantined red cells were considered for transfusion and they were re-instated for cellular component manufacture at their next donation. The efficiency and safety of this strategy were evaluated based on the additional number of components recovered for transfusion and the observed incidence of transfusion transmitted malaria (TTM) respectively. RESULTS: Of the repeat reactive donors, 2696 (> 99.99%) were PCR negative whilst one was PCR positive with very low level parasitaemia. The average number of RBCs and platelets recovered per annum was 64 967 and 7398 representing 7.9 and 5.5% respectively of their annual production. No new TTM cases were recorded and the observed TTM rate of zero was consistent with the upper 95% CI for the pretesting TTM incidence of 0.9 per million donations. CONCLUSION: The study findings support the efficacy and safety of a targeted screening strategy combining a sensitive antibody screening test with a 4-month cellular component restriction period for donors with a declared malarial risk. The TTM risk in Australia remains low and did not measurably change after implementing the testing strategy.

Molecular cloning and disease association of hepatitis G virus: a transfusion-transmissible agent.

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Post-transfusion hepatitis in Australia. Report of the Australian Red Cross study.

Post-transfusion hepatitis developed in 2% of 842 cardiac-surgery patients surveyed in Sydney (4 cases per 1000 units of transfused blood). 3 of the 18 cases were caused by hepatitis B virus even though all units of blood which contained hepatitis B surface antigen (HBsAg) had been rejected. 1 case was caused by cytomegalovirus, and there were 14 (78%) cases of non-A, non-B hepatitis. A significantly higher proportion of the units of blood given to the patients in whom non-A, non-B hepatitis developed contained antibodies against both hepatitis B core antigen and HBsAg than the units of blood given to the other patients. Rejection of blood with these markers of past exposure to hepatitis B may reduce the incidence of post-transfusion non-A, non-B hepatitis by up to a half.

An improved assay for human tetanus anti-toxin and its use in the accession of human plasma for the production of high-titre tetanus immunoglobulin.

A simplified passive haemagglutination (PHA) screening test, an improved quantitative PHA assay, and a stable test cell preparation are described, as well as a comprehensive testing strategy which have been used in concert at this Service over the past 10 years for the successful accession of high-titre tetanus anti-toxin (TAT) plasma for fractionation into human tetanus immunoglobulin (HTIG). The sequential deployment of the screening and quantitative assays, has permitted large numbers of donors to be screened quickly and economically, and has helped establish a significant core of regular donors with high TAT levels. The assays have proven to be highly sensitive and specific and relatively simple to perform, while the coated cells are inexpensive and easily prepared. Approximately 20% of donors screened from the Sydney metropolitan area had TAT levels of 3 IU/ml or greater.

Post-transfusion hepatitis revisited.

OBJECTIVE: To evaluate the risk of post-transfusion and postoperative non-A non-B hepatitis in Australia immediately before the introduction of screening for hepatitis C. DESIGN: Retrospective testing of blood samples from a prospective study of cardiac surgery patients. Samples were taken from transfusion recipients and non-transfused controls at regular intervals for 12 months after surgery during 1987-1989. For all donor, recipient and control samples, alanine aminotransferase (ALT) levels were measured and tests for antibody to hepatitis B (anti-HBc, anti-HBs) and, when available, to hepatitis C (anti-HCV) were performed. SETTING: Cardiac surgery units. PARTICIPANTS: Participants were included if they lived in the metropolitan area, and had not had a transfusion in the past year. MAIN OUTCOME MEASURES: Post-transfusion hepatitis (two consecutive samples showing raised ALT levels, > 90 IU/L with no other known cause); hepatitis C infection and carriage (antibody to hepatitis C). RESULTS: Post-transfusion hepatitis occurred in 1.1% of 736 recipients of blood not screened for hepatitis C (i.e., two cases per 1000 unscreened units given). No hepatitis occurred in 514 controls. Seven of the eight patients with post-transfusion hepatitis seroconverted to hepatitis C virus infection. Seven of the 26 anti-HCV-positive donations transmitted hepatitis C, six of these were positive by recombinant immunoblot assay (RIBA) (one by second generation testing only) and one was RIBA indeterminate. Nineteen were RIBA non-reactive; one transmitted hepatitis but the recipient did not develop anti-HCV, although hepatitis C RNA was detected in the donation. Serum ALT was raised in four of the six infective donations. CONCLUSIONS: Hepatitis C virus infection accounted for almost all cases of non-A non-B post-transfusion hepatitis. First generation anti-HCV tests detected about 85% of infective donations. Surrogate testing of donations by ALT or anti-HBc offers no additional advantage.

Prevalence of hepatitis C virus antibodies in Sydney blood donors.

OBJECTIVE: To determine the prevalence of hepatitis C virus (HCV) antibodies in the Sydney blood donor population. DESIGN: All blood donations collected from Red Cross blood donors in Sydney from February 1990 until April 1991 were tested for HCV antibodies. For those samples found reactive in an anti-HCV screening test, a confirmatory test was carried out for the presence of HCV antibodies and the alanine aminotransferase level was measured. RESULTS: The prevalence of repeated reactivity to the screening test was 0.45% among blood donations overall, and 1.02% in donors giving blood for the first time in the study period. The confirmatory test result was positive for 30.8% of donations found to be repeatedly reactive in the screening test. There was little change over the study period in the HCV antibody prevalence of donors giving blood for the first time, but there was a clear decrease in the prevalence among all donations. Prevalence in males was nearly twice the prevalence in females--a difference which was consistent across age groups. The highest prevalence in both sexes was in the age group 30-34 years. Among samples for which the screening test results was positive, there was a strong correlation between the reactivity recorded for the screening test and both the proportion found positive by the confirmatory test and the proportion with an elevated alanine aminotransferase level. CONCLUSION: The small proportion of blood donations found to be repeatedly reactive by anti-HCV screening and the relatively good correlation with the confirmatory test and liver function assay indicate that a policy of discarding these donations will decrease the risk of transfusion-transmitted HCV infection without materially affecting the supply of blood.

Risk factors for hepatitis C virus infection in blood donors: a case-control study.

OBJECTIVE: To investigate risk factors for hepatitis C virus (HCV) infection in Sydney blood donors. DESIGN: Blood donors confirmed to be positive for HCV antibodies were compared with blood donors with a positive result of a screening assay, but whose HCV antibody status had not been confirmed. A questionnaire on sexual, parenteral and other potential risk factors was administered to both groups. SETTING: Blood Transfusion Service in Sydney. PARTICIPANTS: The study enrolled 220 donors who had confirmed HCV infection, and 210 donors who did not. RESULTS: The relative risk associated with injecting drug use was 63 (95% confidence interval, 19-260) when comparison was made with all other donors. Among donors who did not report injecting drug use, a significant, independent increase in risk was found in association with having had a tattoo. Among donors who did not give a history of parenteral exposure, there was a significantly greater risk in people with more than one life-time sexual partner than in those with at most one partner. CONCLUSION: A history of injecting drug use was elicited as the most important risk factor in Sydney blood donors with antibodies to hepatitis C. Having had a tattoo, and an increased number of lifetime sexual partners were also independently associated with HCV infection.