Paper-based microfluidic electro-analytical device (PMED) for magneto-assay automation: Towards generic point-of-care diagnostic devices

Rapid diagnostic tests (RDTs) for point-of-care (POC) testing of infectious diseases are popular because they are easy to use. However, RDTs have limitations such as low sensitivity and qualitative responses that rely on subjective visual interpretation. Additionally, RDTs are made using paper-bound reagents, which leads to batch-to-batch variability, limited storage stability and detection of only the analytes they were designed for. This work presents the development of a versatile technology, based on short magneto-assays and inexpensive paper-based microfluidic electro-analytical devices (PMEDs). PMEDs were produced locally using low-cost equipment, they were stable at room temperature, easy to use, and provided quantitative and objective results. The devices served to detect alternatively a variety of magneto-assays, granting quantitation of streptavidin-HRP, biotinylated HRP and Pasmodium falciparum lactate dehydrogenase (Pf-LDH) in less than 25 min, using either commercial or customized screen-printed electrodes and measurement equipment. Furthermore, Pf-LDH detection in diluted lysed whole blood displayed a linear response between 3 and 25 ng mL-1, detection and quantification limits ranging between 1 and 3 ng mL-1 and 6-12 ng mL-1, respectively, and provided results that correlated with those of the reference ELISA. In short, this technology is versatile, simple, and highly cost-effective, making it perfect for POC testing.

Association of HLA-B*35 and moderate or severe cutaneous reactions secondary to benznidazole treatment in chronic Chagas disease patients

OBJECTIVES

Benznidazole is the first line treatment for Chagas disease. Adverse events appear in more than 50% of patients, leading to discontinuation in approximately 15%. Cutaneous reactions are one of the most frequent adverse events. HLA-genotyping previous studies identified an association between cutaneous reactions to benznidazole and carrying the specific allele HLA-B*35:05. We designed the present study to prospectively confirm this association.

METHODS

This is a prospective observational study including Chagas disease patients aged 18 years or more who accepted to receive benznidazole treatment following current guidelines. Allele genotyping of HLA-B was determined in all patients. Clinical and analytical follow-up was performed at days 0, 7, 14, 30 and 60 of treatment.

RESULTS

Two-hundred and seven patients were included. Seventy percent were female with a mean age of 45.1 (SD ±9.86) years mainly from Bolivia (92.8%). In 102 (49.3%) cases a cutaneous reaction was diagnosed. Forty-eight (46.6%) were classified as mild, 37 (35.9%) as moderate and 18 (17.5%) as severe. Thirty-two (15.4%) patients had to definitively interrupt the treatment due to a cutaneous reaction. Female sex (OR 4.49; 95%CI 1.62-12.47), new-onset eosinophilia prior to cutaneous symptoms (OR 2.55; 95%CI 1.2-5.43) and carrying the HLA-B*35 allelic group (OR 2.58; 95%CI 1.2-5.51) were all predictors of moderate to severe cutaneous reactions. No statistical significance was found when the specific allele HLA-B*35:05 was analyzed.

CONCLUSIONS

Patients carrying the HLA-B*35 allelic group are at higher risk of moderate to severe reactions when taking benznidazole treatment.

Executive Summary of the Consensus Statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Tropical Medicine and International Health (SEMTSI), the Spanish Association of Surgeons (AEC), the Spanish Society of Pneumology and Thoracic Surgery (SEPAR), the Spanish Society of Thoracic Surgery (SECT), the Spanish Society of Vascular and Interventional Radiology (SERVEI), and the Spanish Society of Paediatric Infectious Diseases (SEIP), on the Management of Cystic Echinococcosis

The Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Tropical Medicine and International Health (SEMTSI), the Spanish Association of Surgeons (AEC), the Spanish Society of Pneumology and Thoracic Surgery (SEPAR), the Spanish Society of Thoracic Surgery (SECT), the Spanish Society of Vascular and Interventional Radiology (SERVEI), and the Spanish Society of Paediatric Infectious Diseases (SEIP) considered it pertinent to issue a consensus statement on the management of cystic echinococcosis (CE) to guide healthcare professionals in the care of patients with CE. Specialists from several fields (clinicians, surgeons, radiologists, microbiologists, and parasitologists) identified the most clinically relevant questions and developed this Consensus Statement, evaluating the available evidence-based data to propose a series of recommendations on the management of this disease. This Consensus Statement is accompanied by the corresponding references on which these recommendations are based. Prior to publication, the manuscript was open for comments and suggestions from the members of the SEIMC and the scientific committees and boards of the various societies involved.

QTc and anti-tuberculosis drugs: a perfect storm or a tempest in a teacup? Review of evidence and a risk assessment

SUMMARY

Multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR-TB) are global concerns, with stagnant treatment success rates of roughly 54% and 30%, respectively. Despite adverse events associated with several DR-TB drugs, newly developed drugs and shorter regimens are bringing hope; recent concern has focused on drugs that prolong the corrected QT interval (QTc). QTc prolongation is a risk factor for torsades de pointe (TdP), a potentially lethal cardiac arrhythmia. While QTc prolongation is used in research as a surrogate marker for drug safety, the correlation between QTc and TdP is not perfect and depends on additional risk factors. The electrocardiogram (ECG) monitoring that has been recommended when new drugs are used has created alarm among clinicians and National Tuberculosis Programmes (NTPs). ECG monitoring is often challenging in high-burden settings where treatment alternatives are limited. According to a review of studies, the prevalence of sudden death directly attributable to TdP by QTc-prolonging DR-TB drugs is likely less than 1%. The risk of death from an ineffective MDR-TB/XDR-TB regimen thus far exceeds the risk of death from arrhythmia. In patients with QTc prolongation who develop cardiac events, other significant risk factors in addition to the drugs themselves are nearly always present. Clinicians and NTPs should be aware of and manage all possible circumstances that may trigger an arrhythmia (hypopotassaemia and human immunodeficiency virus infection are probably the most frequent in DR-TB patients). We present the limited but growing evidence on QTc prolongation and DR-TB management and propose a clinical approach to achieve an optimal balance between access to life-saving drugs and patient safety.

Serodiscordance in chronic Chagas disease diagnosis: a real problem in non-endemic countries

According to the WHO, chronic Chagas disease (CD) diagnosis is based on two serological techniques. To establish a definitive diagnosis, the results must be concordant. In cases of discordances, the WHO proposes repeating serology in a new sample, and if results remain inconclusive, a confirmatory test should be performed. This study, conducted at two Tropical Medicine Units in Europe over 4 years, aims to assess the diagnostic yield of TESA- (trypomastigote excreted-secreted antigens) blot as a confirmatory technique in patients with inconclusive and discordant results. Of 4939 individuals screened, 1124 (22.7%) obtained positive results and 165 (3.3%) discordant results. Serology was repeated in 88/165 sera and discrepancies were solved in 25/88 (28.4%) cases. Patients without a definitive diagnosis were classified in two different groups: Group 1, including patients with inconclusive results despite retesting (n = 63), and Group 2, including patients with discordant results not retested (n = 77). TESA-blot was performed for all of Group 1 and 39/77 of Group 2 and was positive for 33/63 (52.4%) and 21/39 (53.8%), respectively. Analysis of Group 1 results showed a moderate agreement between results of the ELISA based on native antigen and TESA-blot (κ 0.53). In contrast, a clear disagreement was observed between the ELISA based on recombinant antigens and TESA-blot (κ <0). A sizeable proportion of patients are suspected to have CD with inconclusive results or in whom re-testing is not feasible. TESA-blot was positive in half of these patients, highlighting the need for a confirmatory assay in European centres caring for exposed individuals.

Immunosuppression and Chagas disease; experience from a non-endemic country

Reactivation of Chagas disease in the chronic phase may occur when immunosuppression is established, sometimes resulting in high parasitaemia and severe clinical manifestations such as meningitis and meningoencephalitis. Although this situation is being increasingly described, there is still scarce information. This retrospective observational study was performed in three Tropical Medicine Units of Barcelona (Spain) included in the International Health Programme of the Catalan Health Institute (PROSICS). The objective of the study was to describe epidemiological, clinical, microbiological, prognostic and therapeutic data from patients with Chagas disease and any kind of immunosuppressive condition attended in these three institutions from January 2007 to October 2014. From 1823 patients with Chagas disease attending these three centres during the study period, 38 (2%) had some kind of immunosuppressive condition: 12 patients had human immunodeficiency virus infection, 8 patients had neoplasia, 4 patients underwent organ transplantation and 14 patients had an autoimmune disease. Eight (21.1%) patients had cardiac involvement, and six (15.8%) patients had gastrointestinal involvement. Acute Trypanosoma cruzi infection was detected in two Spanish patients. Thirty-one (81.6%) patients received treatment with benznidazole, of whom 17 (54.8%) had some kind of adverse event. No patient had a severe manifestation or reactivation of Chagas disease. Patients with Chagas disease under immunosuppressive conditions are being increasingly described, especially in non-endemic countries. More information about this topic is required and international consensus in the diagnosis, treatment and follow up of these patients must be established to reduce the morbidity and mortality.

Anti-SSA/Ro52 autoantibodies in scleroderma: results of an observational, cross-sectional study

OBJECTIVES

To date, the diagnostic utility of anti-SSA/Ro52 autoantibodies in scleroderma and the association of them with certain clinical manifestations, particularly inflammatory myositis, are still controversial. This paper aims to assess the correlation between the presence of anti-SSA/Ro52 antibodies and the demographic, clinical and prognosis characteristics of patients with systemic sclerosis (SSc).

METHODS

This is a retrospective, cross-sectional and observational study in patients with SSc. Baseline demographic and clinical characteristics were recorded. Presence of anti-SSA/Ro52, anti-SSA/Ro, anti-SSB/La, snRNP/Sm, anti-centromere, anti-Scl-70 and anti-PM-Scl were analysed by immunoblot, and antinuclear antibodies (ANA) by indirect immunofluorescence. Statistical analysis was performed with PASW Statics 18 software.

RESULTS

A total of 132 consecutive patients with analysis of anti-SSA/Ro52 antibodies were selected from a Spanish cohort of 408 patients with SSc, 87.1% of them being women. About half of patients had the limited form (51.5%), followed by diffused form (18.9%), sclerosis sine scleroderma (22.7%), and pre-scleroderma (6.8%). Prevalence of anti-SSA/Ro52 was 35.6%. No association between anti-SSA/Ro52 and clinical manifestations was found, while detection of anti-SSA/Ro52 was significantly associated with the presence of anti-Ro.

CONCLUSIONS

The results of our study show that anti-SSA/Ro52 antibodies are often found in SSc patients. No clinical manifestations, including inflammatory myopathy, were related with anti-SSA/Ro antibodies.