Transfusion-transmitted bacterial infections cause significant patient morbidity and mortality. This study aimed to improve the sensitivity of a nucleic acid-based electrochemiluminescence (ECL) assay for pretransfusion bacterial testing of cellular blood components. The approach is dependent on the detection of bacterial 16S ribosomal RNA (rRNA). The modifications studied included the use of a chaotrope-based lysis buffer with high-energy mechanical cell disruption by RiboLysis, increased ruthenium (Ru2+) labelling per 16S rRNA molecule and concomitant use of fluorescent nucleic acid dyes (CyQUANT, Syto 17 red and Syto 61 red). The methodological changes made did lead to more effective bacterial cell disruption and enhanced ECL signal generation. Nevertheless, assay sensitivity was only slightly improved at approximately 10(4)-10(5) colony forming units per mL (CFU mL(-1)) and the results were highly inconsistent. The method is still not sensitive to the required 10(2) CFU mL(-1) and remains impractical for routine use in blood centres. 相似文献
Introduction: Infection with hepatitis E virus (HEV) is the commonest cause of acute hepatitis worldwide. This infection, with fecal-oral transmission, was previously thought to be limited to humans residing in developing countries with poor sanitation, spreading via contaminated drinking water. In recent years, our understanding of epidemiology and clinical spectrum of this infection have changed markedly.
Areas covered: This article reviews the epidemiology, including routes of transmission, and clinical manifestations of HEV infection around the world. In addition, recent findings on transmission-associated HEV infection, extrahepatic manifestations of hepatitis E and chronic infection with HEV, and treatment and prevention of this infection are discussed.
Expert commentary: HEV infection has two distinct epidemiologic forms and clinical patterns of disease: (i) acute epidemic or sporadic hepatitis caused by fecal-oral (usually water-borne) transmission of genotype 1 and 2 HEV from a human reservoir in areas with poor hygiene and frequent water contamination, and (ii) infrequent sporadic hepatitis E caused by zoonotic infection, possibly from an animal source through ingestion of undercooked animal meal, of genotype 3 or 4 virus. In disease-endemic areas, pregnant women are at a particular risk of serious disease and high mortality. In less-endemic areas, chronic infection with HEV among immunosuppressed persons is observed. HEV can also be transmitted through Transfusion of blood and blood products. Ribivirin treatment is effective in chronic hepatitis E. Two efficacious vaccines have been tried in humans; one of these has received marketing approval in its country of origin. 相似文献
Direct measurement of the risk of transfusion-transmitted infection (TTI) is practical and accurate only if the level of risk is high. Historically, studies that established frozen repositories of transfusion recipient and/or blood donor samples were important in establishing the risk of many TTI agents, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). However, given the current very low risk of TTI, mathematical modelling is necessary to estimate the magnitude of such a risk. For agents for which routine blood donor screening is performed, most of this risk comes from transfusion of units collected in the window period between donor infection and a positive blood screening assay. The incidence/window period model has been used to estimate the magnitude of such risks (of the order of 1:100 000 to 1:1 000 000) and for predicting the extent of risk reduction that can be expected with implementation of new tests. Direct estimation and mathematical modelling approaches are both important tools for future assessment of potential, new or emerging TTI agents. 相似文献
SUMMARY. The risk of Epstein—Barr virus (EBV) infection after blood transfusion has been controversially discussed. Little is known about EBV transmission via buffy-coat-depleted red cell concentrates (RCC). In this study, we determined the number of EBV genomes in RCC of EBV-seropositive donors in comparison to whole blood. RCC were prepared from whole blood donations by using the 'top and bottom system'. Leucocyte content was significantly reduced in RCC in comparison to whole blood (0.47 times 109 vs. 2.3 times 109 per unit; P < 0.001). As B cells are expected to harbour EBV genomes, we analysed the number of B lymphocytes in both types of blood products. There was a significant reduction of B cell content from a median value of 90 times 106 in whole blood to 0.2 times 106 in RCCs ( P < 0.001). The number of EBV genomes was estimated at a median value of seven from 106 B cells in the peripheral blood of healthy, EBV-seropositive blood donors by means of a polymerase chain reaction (PCR) assay. By calculation, one unit of RCC may contain an average of one to two EBV genomes, in contrast to a whole blood unit, which is likely to harbour an average of 600 to 700 EBV genomes. It is concluded that the use of leucocyte depletion systems significantly reduces the number of EBV genomes in erythrocyte concentrates. Thus, leucocyte reduced blood products appear to minimize the risk of EBV infection. 相似文献
BACKGROUND AND OBJECTIVES: Transfusion-transmitted hepatitis B virus (TT-HBV) infections, when analysed in detail provide information about the nature and relative frequency of the sources of infectious donations. These cases are therefore used to inform blood safety strategies. This study updates previous reviews of the causes of TT-HBV in order to determine whether a change may have occurred in recent years. MATERIALS AND METHODS: Cases of TT-HBV reported during 1998-2001 were reviewed and the nature of the infectious donations described. These cases were compared to a previously published case series reported during 1991-97. RESULTS: Six cases of TT-HBV have been reported in the UK between 1998 and 2001. All were the result of infectious donations collected from donors with acute HBV infection. This is in contrast to the series reported during 1991-97 when only three of 14 similar cases were caused by acute infections in donors, with the majority of incidents being the result of chronic infection in donors. CONCLUSIONS: There appears to have been a change in the relative importance of acute and chronic HBV infection in blood donors in causing TT-HBV infections. Improvements in the sensitivity of HBsAg assays and/or a decrease in the prevalence of chronic HBV infection in blood donors could explain this observation. This change may have implications for strategies to reduce the risk of TT-HBV infection. 相似文献
The potential role of transfusion-transmitted virus (TTV) infection in determining liver damage is poorly understood and no information exists about TTV replication within hepatocytes. In this study, we assess TTV in situ PCR in liver tissue. Twenty-one patients with different degrees of liver damage were studied by both serum TTV-DNA detection and in situ TTV PCR analysis and extractive PCR in liver biopsy paraffin sections (FFPE). Extractive PCR and in situ PCR detected TTV-DNA both in serum and liver tissue of five patients. The presence of TTV in serum matched with that found in the liver and TTV sequences were never found independently in liver or serum. Four out of five TTV-DNA-positive patients have not other known cause of liver damage while in one a coinfection from HCV was observed. Our data indicate that in situ PCR appears to be a reliable tool for the detection of TTV-DNA in FFPE, and may help detecting unknown origin of liver damage. 相似文献