Multiplex detection of blood-borne pathogens on a self-driven microfluidic chip using loop-mediated isothermal amplification.

Detection of blood-borne pathogens such as hepatitis C virus (HCV), hepatitis B virus (HBV) and human immunodeficiency virus (HIV) is essential to ensure the safety of blood transfusion. However, traditional PCR-based pathogen nucleic acid detection methods require relatively high experimental facilities and are difficult to apply in areas with limited resources. In this study, a self-driven microfluidic chip was designed to carry out multiplex detection of HBV, HCV and HIV by using loop-mediated isothermal amplification (LAMP). Benefitting from the air permeability of the polydimethylsiloxane material, the chip could accomplish sample loading within 12 min driven by the pressure difference between the reaction chambers and vacuum chambers in the chip without using pumps or any injection devices. Multiplex detection is achieved by presetting LAMP primers specific to different targets in different reaction chambers. Calcein was used as an indicator to indicate the positive amplification reaction, and the result can be recorded by a smartphone camera. After 50 min of isothermal amplification at 63 °C, 2 copies/µL of HBV, HCV and HIV target nucleic acids could be detected. The results of HBV detection of 20 clinical plasma samples by using the chip are consistent with that of the qPCR-based kit, indicating that the LAMP-based self-driven chip has the clinical application potential for blood-borne pathogen detection, especially in resource-limited areas.

Race/Ethnic and Educational Disparities in the Association Between Pathogen Burden and a Laboratory-Based Cumulative Deficits Index.

BACKGROUND: Disparities in adult morbidity and mortality may be rooted in patterns of biological dysfunction in early life. We sought to examine the association between pathogen burden and a cumulative deficits index (CDI), conceptualized as a pre-clinical marker of an unhealthy biomarker profile, specifically focusing on patterns across levels of social disadvantage. METHODS: Using the data from the National Health and Nutrition Examination Survey 2003-2004 wave (aged 20-49 years), we examined the association of pathogen burden, composed of seven pathogens, with the CDI. The CDI comprised 28 biomarkers corresponding to available clinical laboratory measures. Models were stratified by race/ethnicity and education level. RESULTS: The CDI ranged from 0.04 to 0.78. Nearly half of Blacks were classified in the high burden pathogen class compared with 8% of Whites. Among both Mexican Americans and other Hispanic groups, the largest proportion of individuals were classified in the common pathogens class. Among educational classes, 19% of those with less than a high school education were classified in the high burden class compared with 7% of those with at least a college education. Blacks in the high burden pathogen class had a CDI 0.05 greater than those in the low burden class (P < 0.05). Whites in the high burden class had a CDI only 0.03 greater than those in the low burden class (P < 0.01). DISCUSSION: Our findings suggest there are significant social disparities in the distribution of pathogen burden across race/ethnic groups, and the effects of pathogen burden may be more significant for socially disadvantaged individuals.

Seroprevalence and demographic factors associated with hepatitis B, hepatitis C and HIV infection from a hospital emergency department testing programme, London, United Kingdom, 2015 to 2016.

BackgroundProgress towards HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) elimination requires local prevalence estimates and linkage to care (LTC) of undiagnosed or disengaged cases.AimWe aimed to estimate seroprevalence, factors associated with positive blood-borne virus (BBV) serology and numbers needed to screen (NNS) to detect a new BBV diagnosis and achieve full LTC from emergency department (ED) BBV testing.MethodsDuring a 9-month programme in an ED in east London, England, testing was offered to adult attendees having a full blood count (FBC). We estimated factors associated with positive BBV serology using logistic regression and NNS as the inverse of seroprevalence. Estimates were weighted to the age, sex and ethnicity of the FBC population.ResultsOf 6,211 FBC patients tested, 217 (3.5%) were positive for at least one BBV. Weighted BBV seroprevalence was 4.2% (95% confidence interval (CI): 3.6-4.9). Adjusted odds ratios (aOR) of positive BBV serology were elevated among patients that were: male (aOR: 2.7; 95% CI: 1.9-3.9), 40-59 years old (aOR: 1.9; 95% CI: 1.4-2.7), of Black British/Black other ethnicity (aOR: 1.8; 95% CI: 1.2-2.8) or had no fixed address (aOR: 2.9; 95% CI: 1.5-5.5). NNS to detect a new BBV diagnosis was 154 (95% CI: 103-233) and 135 (95% CI: 93-200) to achieve LTC.ConclusionsThe low NNS suggests routine BBV screening in EDs may be worthwhile. Those considering similar programmes should use our findings to inform their assessments of anticipated public health benefits.

Understanding how, why, for whom, and under what circumstances opt-out blood-borne virus testing programmes work to increase test engagement and uptake within prison: a rapid-realist review.

BACKGROUND: Prisons represent a unique opportunity to diagnose blood-borne viruses. Opt-out testing is receiving increasing interest, as a result of mounting evidence to suggest that the manner in which a test offer is delivered, affects test uptake. Although the effectiveness of opt-out testing within the prison setting has been established, robust explanations are required for the variation in outcomes reported. METHODS: Rapid-realist review methodology was used to synthesise the literature on prison-based opt-out testing. The review was carried out in three phases. Phase one: An expert panel provided literature relevant to the implementation of opt-out testing within the English prison estate. Unstructured searches were also conducted to identify other social programmes where "opt-out" had been used to increase uptake. Phase two: a systematic search of six peer-review and five grey literature databases was carried out to identify empirical data on opt-out testing within the prison setting. Phase three: Additional non-exhaustive searches were carried out to identify literature that reinforced emergent concepts. The development of programme theory took place with each iteration and was validated in consultation with stakeholders. RESULTS: Programme theory was constructed for two outcomes: the proportion of intake offered a test and the proportion offered that accepted testing. The proportion of intake offered testing was influenced by the timing of the test offer, which was often delayed due to barriers to prisoner access. The decision to accept testing was influenced by concerns about confidentiality, fear of a positive diagnosis, a prisoner's personal interpretation of risk, discomfort with invasive procedures, trust in healthcare, and the fidelity of the opt-out offer. CONCLUSIONS: This review identified important implementation considerations that moderate the effectiveness of opt-out testing programmes. It also highlighted a lack of appreciation for the theoretical underpinnings of opt-out programmes and tension around how to implement testing in a manner that adheres to both default theory and informed consent. It is anticipated that results will be used to inform the design and implementation of subsequent versions of these programmes, as well as catalyse further in-depth analysis into their operation within the unique context of prison. REVIEW REGISTRATION: CRD42017068342 .

Transfusion of pathogen-reduced platelet components without leukoreduction.

BACKGROUND: Leukoreduction (LR) of platelet concentrate (PC) has evolved as the standard to mitigate risks of alloimmunization, clinical refractoriness, acute transfusion reactions (ATRs), and cytomegalovirus infection, but does not prevent transfusion-associated graft-versus-host disease (TA-GVHD). Amotosalen-ultraviolet A pathogen reduction (A-PR) of PC reduces risk of transfusion-transmitted infection and TA-GVHD. In vitro data indicate that A-PR effectively inactivates WBCs and infectious pathogens. STUDY DESIGN AND METHODS: A sequential cohort study evaluated A-PR without LR, gamma irradiation, and bacterial screening in hematopoietic stem cell transplant (HSCT) recipients. The first cohort received conventional PC (control) processed without LR, but with gamma irradiation and bacterial screening. The second cohort received A-PR PC (test) processed without: LR, bacterial screening, or gamma irradiation. The primary efficacy outcome was the 1-hour corrected count increment. The primary safety outcome was treatment-emergent ATR. Secondary outcomes included clinical refractoriness, and 100-day status for engraftment, TA-GVHD, HSCT-GVHD, infections, and mortality. RESULTS: Mean corrected count increment (× 103 ) of 33 test PC recipients was similar (18.9 ± 8.8 vs. 16.6 ± 8.4; p = 0.296) to that of 31 control PC recipients. Test recipients had a reduced, but nonsignificant, incidence of ATR (test = 9.1%, Control = 19.4%; p = 0.296). The frequencies of clinical refractoriness (0 of 33 vs. 4 of 31 patients) and refractory transfusions (6.6% vs. 19.3%) were lower in the test cohort (p = 0.05 and 0.02), respectively. No patient in either cohort had TA-GVHD. Day 100 engraftment, HSCT-GVHD, mortality, and infectious disease complications were similar between cohorts. CONCLUSIONS: This study indicated that A-PR PC without LR, gamma irradiation, or bacterial screening is feasible for support of HSCT.

Implementing routine blood-borne virus testing for HCV, HBV and HIV at a London Emergency Department - uncovering the iceberg?

UK guidelines recommend routine HIV testing in high prevalence emergency departments (ED) and targeted testing for HBV and HCV. The 'Going Viral' campaign implemented opt-out blood-borne virus (BBV) testing in adults in a high prevalence ED, to assess seroprevalence, uptake, linkage to care (LTC) rates and staff time taken to achieve LTC. Diagnosis status (new/known/unknown), current engagement in care, and severity of disease was established. LTC was defined as patient informed plus ⩾1 clinic visit. A total of 6211/24 981 ED attendees were tested (uptake 25%); 257 (4.1%) were BBV positive (15 co-infected), 84 (33%) required LTC. 100/147 (68%) HCV positives were viraemic; 44 (30%) required LTC (13 new, 16 disengaged). 26/54 (48%) HBV required LTC (seven new, 11 disengaged). 16/71 (23%) HIV required LTC (10 new, five disengaged). 26/84 (31%) patients requiring LTC had advanced disease (CD4 1, Fibroscan F3/F4 or liver cancer), including five with AIDS-defining conditions and three hepatocellular carcinomas. There were five BBV-related deaths. BBV prevalence was high (4.1%); most were HCV (2.4%). HIV patients were more successfully and quickly LTC than HBV or HCV patients. ED testing was valuable as one-third of those requiring LTC (new, disengaged or unknown status patients) had advanced disease.

Trends of blood-borne infectious diseases in a rural blood donation center of southeast Gabon (Koula-Moutou).

INTRODUCTION: Blood-borne pathogens such as human immunodeficiency virus (HIV), hepatitis B and C (HBV and HCV) viruses and Treponema pallidum remain a major public health problem in sub-Saharan Africa. The purpose of this study was to assess the frequency and clinical implications of HIV, HBV, HCV and Treponema pallidum markers in blood donors in a rural area of Southeast Gabon (Koula-Moutou) from 2012 to 2017. METHODS: Hepatitis B surface antigen (HBsAg), anti-HIV, anti-HCV and anti-Treponema pallidum antibodies were screened using rapid diagnostic tests (RDTs). RESULTS: Of a total of 5,706 blood donors, 1,054 (18.5%) were seropositive for at least one infectious marker and 59 (5.6%) had serologic evidence of multiple infections. The overall seroprevalence of HIV, HBsAg, HCV, and syphilis was 3.1%; 5.9%; 6.2% and 3.3%, respectively. HIV, syphilis and HCV distributions were associated with neither the sex nor the age of the donors. Only HBsAg seroprevalence was significantly higher in donors of the age group 26-35 years old compared to donors of the age group 36-45 years (OR = 1.43 (95% CI: 1.01-2.04), P = 0.045). There was a significant increase in the frequencies of HIV and syphilis and a regression of HBsAg and HCV among blood donors. CONCLUSION: This study presents the epidemiology of the main pathogens detected in blood donors in a rural area in Gabon. We found that the overall distribution of transfusion transmitted infectious diseases were lower than those observed in the general population but could be underestimated due to the use of RDTs in the screening process of the blood donations.

Small bowel dilation in children with short bowel syndrome is associated with mucosal damage, bowel-derived bloodstream infections, and hepatic injury.

BACKGROUND: Liver disease occurs frequently in short bowel syndrome. Whether small bowel dilation in short bowel syndrome could influence the risk of liver injury through increased bacterial translocation remains unknown. Our aim was to analyze associations between small bowel dilation, mucosal damage, bloodstream infections, and liver injury in short bowel syndrome patients. METHODS: Among short bowel syndrome children (n = 50), maximal small bowel diameter was measured in contrast series and expressed as the ratio to the height of the fifth lumbar vertebra (small bowel diameter ratio), and correlated retrospectively to fecal calprotectin and plasma citrulline-respective markers of mucosal inflammation and mass-bloodstream infections, liver biochemistry, and liver histology. RESULTS: Patients with pathologic small bowel diameter ratio >2.17 had increased fecal calprotectin and decreased citrulline (P < .04 each). Of 33 bloodstream infections observed during treatment with parenteral nutrition, 16 were caused by intestinal bacteria, cultured 15 times more frequently when small bowel diameter ratio was >2.17 (P < .001). Intestinal bloodstream infections were predicted by small bowel diameter ratio (odds ratio 1.88, P = .017), and their frequency decreased after operative tapering procedures (P = .041). Plasma bilirubin concentration, gamma-glutamyl transferase activity, and histologic grade of cholestasis correlated with small bowel diameter ratio (0.356-0.534, P < .014 each), and were greater in the presence of intestinal bloodstream infections (P < .001 for all). Bloodstream infections associated with portal inflammation, cholestasis, and fibrosis grades (P < .031 for each). In linear regression, histologic cholestasis was predicted by intestinal bloodstream infections, small bowel diameter ratio, and parenteral nutrition (ß = 0.36-1.29; P < .014 each), while portal inflammation by intestinal bloodstream infections only (ß = 0.62; P = .033). CONCLUSION: In children with short bowel syndrome, small bowel dilation correlates with mucosal damage, bloodstream infections of intestinal origin, and cholestatic liver injury. In addition to parenteral nutrition, small bowel dilation and intestinal bloodstream infections contribute to development of short bowel syndrome-associated liver disease.

Pathogen reduction/inactivation of products for the treatment of bleeding disorders: what are the processes and what should we say to patients?

Patients with blood disorders (including leukaemia, platelet function disorders and coagulation factor deficiencies) or acute bleeding receive blood-derived products, such as red blood cells, platelet concentrates and plasma-derived products. Although the risk of pathogen contamination of blood products has fallen considerably over the past three decades, contamination is still a topic of concern. In order to counsel patients and obtain informed consent before transfusion, physicians are required to keep up to date with current knowledge on residual risk of pathogen transmission and methods of pathogen removal/inactivation. Here, we describe pathogens relevant to transfusion of blood products and discuss contemporary pathogen removal/inactivation procedures, as well as the potential risks associated with these products: the risk of contamination by infectious agents varies according to blood product/region, and there is a fine line between adequate inactivation and functional impairment of the product. The cost implications of implementing pathogen inactivation technology are also considered.

A nurse-led intervention improved blood-borne virus testing and vaccination in Victorian prisons.

OBJECTIVES: Testing is the first step in treatment and care for blood-borne viruses (BBVs) and sexually transmitted infections (STIs). As new treatments for viral hepatitis emerge, it is important to document effective models for BBV/STI testing. A nurse-led intervention was implemented across three prisons in Victoria to improve BBV/STI testing. We evaluated the impact of the intervention on BBV/STI testing rates and hepatitis B (HBV) vaccination for reception prisoners. METHODS: BBV/STI testing and HBV vaccination data were collected from the medical files of 100 consecutive reception prisoners at three prisons (n=300) prior to and after the intervention was implemented. RESULTS: BBV testing increased significantly from 21% of prisoners to 62% post-intervention. Testing for some STIs increased significantly, but remained low: 5% to 17% for chlamydia and 1% to 5% for gonorrhoea. HBV vaccination increased significantly from 2% to 19%. CONCLUSIONS: The nurse-led intervention resulted in substantially increased testing and vaccination, demonstrating the benefits of a concerted effort to improve BBV and STI management in correctional settings. IMPLICATIONS: The availability of new treatments for hepatitis C has precipitated expansion of treatment in prisons. Improving the testing rate of prisoners, the first step in the treatment cascade, will maximise the benefits.

Metagenomic analysis of bloodstream infections in patients with acute leukemia and therapy-induced neutropenia.

Leukemic patients are often immunocompromised due to underlying conditions, comorbidities and the effects of chemotherapy, and thus at risk for developing systemic infections. Bloodstream infection (BSI) is a severe complication in neutropenic patients, and is associated with increased mortality. BSI is routinely diagnosed with blood culture, which only detects culturable pathogens. We analyzed 27 blood samples from 9 patients with acute leukemia and suspected BSI at different time points of their antimicrobial treatment using shotgun metagenomics sequencing in order to detect unculturable and non-bacterial pathogens. Our findings confirm the presence of bacterial, fungal and viral pathogens alongside antimicrobial resistance genes. Decreased white blood cell (WBC) counts were associated with the presence of microbial DNA, and was inversely proportional to the number of sequencing reads. This study could indicate the use of high-throughput sequencing for personalized antimicrobial treatments in BSIs.

Prevalence and epidemiology of blood borne pathogens in health care workers of Rawalpindi/Islamabad.

OBJECTIVE: To attempt to trace the molecular epidemiology of blood-borne diseases in the hospital community of Pakistan. METHODS: The cross-sectional study was conducted at three major hospitals of Rawalpindi and Islamabad from January to May, 2014.The prevalence of three blood-borne pathogens hepatitis B and C as well as human immunodeficiency virus was investigated in hospital workers of different occupations. Initial screening was performed with immuno-chromatographic technique followed by enzyme-linked immune-sorbent assay. Positive samples were subjected to real time polymerase chain reaction amplification of specific viral sequences for amplification with universal as well as genotype-specific primers. RESULTS: Out of total 500 subjects, there were 42(8.4%) doctors, 101(20.2%) nurses, 92(18.4%) technicians, 67(13.4%) ward boys, 41(8.2%) sweepers, 36(7.2%) security guards and 122(24.4%) administrative workers. None was positive for the presence of human immunodeficiency virus after initial screening with immuno-chromatographic technique. In case of hepatitis viruses, 9(0.18%) samples were positive for anti-hepatitis C virus and 3(0.6%) for hepatitis B surface antigen. Three (2.97%) nurses and 3(3.29%) lab technicians were at the highest risk of exposure. CONCLUSIONS: Human immunodeficiency virus was not present among the healthcare workers, while the prevalence of hepatitis B and C viruses was far less compared to the general population.

Risks associated with red blood cell transfusions: potential benefits from application of pathogen inactivation.

BACKGROUND: Red blood cell (RBC) transfusion risks could be reduced if a robust technology for pathogen inactivation of RBC (PI-RBCs) were to be approved. MATERIALS AND METHODS: Estimates of per-unit and per-patient aggregate infectious risks for conventional RBCs were calculated; the latter used patient diagnosis as a determinant of estimated lifetime exposure to RBC units. Existing in vitro data for the two technologies under development for producing PI-RBCs and the status of current clinical trials are reviewed. RESULTS: Minimum and maximum per-unit risk were calculated as 0.0003% (1 in 323,000) and 0.12% (1 in 831), respectively. The minimum estimate is for known lower-risk pathogens while the maximal estimate also includes an emerging infectious agent (EIA) and endemic area Babesia risk. Minimum and maximum per-patient lifetime risks by diagnosis grouping were estimated as 1.5 and 3.3%, respectively, for stem cell transplantation (which includes additional risk for cytomegalovirus transmission); 1.2 and 3.7%, respectively, for myelodysplastic syndrome; and 0.2 and 44%, respectively, for hemoglobinopathy. DISCUSSION: There is potential for PI technologies to reduce infectious RBC risk and to provide additional benefits (e.g., prevention of transfusion-associated graft-versus-host disease and possible reduction of alloimmunization) due to white blood cell inactivation. PI-RBCs should be viewed in the context of having a fully PI-treated blood supply, enabling a blood safety paradigm shift from reactive to proactive. Providing insurance against new EIAs. Further, when approved, the use of PI for all components may catalyze operational changes in blood donor screening, laboratory testing, and component manufacturing.

Expanded blood borne virus testing in a tuberculosis clinic. A cost and yield analysis.

OBJECTIVES: Testing for HIV is a standard of care for people with active tuberculosis (TB). People investigated for TB in the UK often originate from areas with a high prevalence of HIV and other blood borne viruses (BBV). However, assessment for these infections is patchy. We determined the yield and costs of different testing strategies for BBV in a UK TB clinic. METHODS: Since 2009, it has been routine to test all TB clinic attendees. Demographic, clinical and virological data were retrospectively extracted from patient notes and hospital databases. RESULTS: Over 3 years, 1036 people were assessed in the TB service. 410 had a final diagnosis of active TB. HIV testing of the latter population diagnosed 27 new HIV cases at a cost of £3017. When BBV testing was offered to all clinic attendees, a further 6 (total 33) new HIV, 5 Hepatitis B (HBV) and 2 Hepatitis C (HCV) diagnoses were made at a total cost of £22,170. CONCLUSIONS: We have identified previously undiagnosed HIV, HBV and HCV in a TB clinic population. Our data suggest that despite increasing upfront expense, the associated yield argues strongly for BBV testing to be offered to all patients being investigated for possible TB, irrespective of their final diagnosis.

The use of rapid diagnostic tests for transfusion infectious screening in Africa: a literature review.

Infectious risk associated with blood transfusion remains a major public health challenge in Africa, where prevalence rates of the major transfusion-transmissible infections (ie, hepatitis B, hepatitis C, human immunodeficiency virus, and syphilis) are among the highest in the world. Resource-limited blood services often operate with minimal predonation screening safeguards, prompting exclusive reliance on laboratory testing to mitigate infectious risk. Transfusion screening with rapid diagnostic tests (RDTs) has been adopted in areas that lack the capacity to support the routine use of more sophisticated technologies. However, uncertainty surrounding the performance of some RDTs in the field has spurred debate regarding their application to blood donation screening. Our review of the literature identified 17 studies that evaluated RDTs for the infectious screening of blood donors in Africa. The review highlights the variable performance of available RDTs and the importance of their use in a quality-assured manner. Deficiencies in performance observed with some RDTs underscore the need to validate test kits prior to use under field conditions with locally acquired samples. Suboptimal sensitivities of some available tests, specifically hepatitis B virus rapid assays, question their suitability in single-test algorithms, particularly in high-prevalence regions. Although RDTs have limitations, many of which can be addressed through improved training and quality systems, they are frequently the only viable option for infectious screening in resource-poor African countries. Therefore, additional studies and specific guidelines regarding the use of RDTs in the context of blood safety are needed.