Malaria quantitative POC testing using magnetic particles, a paper microfluidic device and a hand-held fluorescence reader.

A point-of-care (POC) device is reported for highly sensitive and selective detection of Plasmodium falciparum lactate dehydrogenase (Pf-LDH), a biomarker of malaria infection, based on a single-step magneto-immunoassay, a single-use microfluidic paper device and a customized hand-held fluorescence reader. The single-step magneto-immunoassay consists in a single 5-min incubation of immuno-modified magnetic particles (c-MAb-MPs), biotinylated detection antibody (bd-MAb), and an enzymatic signal amplifier (Poly-HRP). After on-chip MP concentration and washing, signal generation is achieved by adding a fluorescent enzymatic substrate (QuantaRed). Fluorescence signal is measured using a low-cost customized, portable, and sensible fluorescent detector. The POC affords quantitative Pf-LDH detection in <20 min, with a detection limit of 0.92 ng mL-1 (equivalent to 4.6 parasites µL-1). Furthermore, Pf-LDH quantitation in clinical samples correlates with that provided by the reference ELISA, is more sensitive than a commercial rapid diagnostic test (RDT) and entails little user intervention. These results show that fluorescent paper-based microfluidic devices can be exploited to simplify magneto-immunoassay handling, taking this type of test closer to the requirements of POC testing.

Neisseria gonorrhoeae culture growth rates from asymptomatic individuals with a positive nucleic acid amplification test.

Gonorrhoea infections are frequently diagnosed at extragenital locations in asymptomatic individuals and are historically related to poor recovery in culture, which hinders antimicrobial susceptibility testing. The aim of this study was to evaluate recovery rates of Neisseria gonorrhoeae by culture among asymptomatic individuals who tested positive by nucleic acid amplification tests between 2018 and 2019 in Barcelona (Spain). In total, 10 396 individuals were tested for N. gonorrhoeae on first-void urine, rectal, pharyngeal and/or vaginal swabs depending on sexual behaviour. Overall infection prevalence was 5·5% (95% confidence interval [CI] 5·0-5·9). Seven hundred and ten samples were positive corresponding to 567 individuals. The most common site of infection was the pharynx (71·3%), followed by rectum (23·1%) and genitals (4·7%) (P < 0·0001). The N. gonorrhoeae recovery rate in culture, time from positive screening to culture specimen and inoculation delay were calculated. Recovery rate was 21·7% in pharynx, 66·9% in rectum and 37·0% in genitals (25·0% vagina, 71·4% urethra) (P < 0·0001). Median culture collection time was 1 [0; 3] days, and median inoculation delay was 5·01 [4·99-7·99] h, with no impact on N. gonorrhoeae recovery, P = 0·8367 and P = 0·7670, respectively. Despite efforts towards optimizing pre-analytical conditions, the N. gonorrhoeae recovery rate in asymptomatic individuals is unacceptably low (especially for pharynx), representing a problem for monitoring antimicrobial-resistant infections.

Efficacy and safety assessment of different dosage of benznidazol for the treatment of Chagas disease in chronic phase in adults (MULTIBENZ study): study protocol for a multicenter randomized Phase II non-inferiority clinical trial.

BACKGROUND: Chagas disease (CD) continues to be a neglected infectious disease with one of the largest burdens globally. Despite the modest cure rates in adult chronic patients and its safety profile, benznidazole (BNZ) is still the drug of choice. Its current recommended dose is based on nonrandomized studies, and efficacy and safety of the optimal dose of BNZ have been scarcely analyzed in clinical trials. METHODS/DESIGN: MULTIBENZ is a phase II, randomized, noninferiority, double-blind, multicenter international clinical trial. A total of 240 patients with Trypanosoma CD in the chronic phase will be recruited in four different countries (Argentina, Brazil, Colombia, and Spain). Patients will be randomized to receive BNZ 150 mg/day for 60 days, 400 mg/day for 15 days, or 300 mg/day for 60 days (comparator arm). The primary outcome is the efficacy of three different BNZ therapeutic schemes in terms of dose and duration. Efficacy will be assessed according to the proportion of patients with sustained parasitic load suppression in peripheral blood measured by polymerase chain reaction. The secondary outcomes are related to pharmacokinetics and drug tolerability. The follow-up will be 12 months from randomization to end of study participation. Recruitment was started in April 2018. CONCLUSION: This is a clinical trial conducted for the assessment of different dose schemes of BNZ compared with the standard treatment regimen for the treatment of CD in the chronic phase. MULTIBENZ may help to clarify which is the most adequate BNZ regimen in terms of efficacy and safety, predicated on sustained parasitic load suppression in peripheral blood. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03191162. Registered on 19 June 2017.

Pregnancy outcomes after maternal Zika virus infection in a non-endemic region: prospective cohort study.

OBJECTIVES: The aim was to describe pregnancy outcomes after Zika virus (ZIKV) infection in a non-endemic region. METHODS: According to the Spanish protocol issued after the ZIKV outbreak in Brazil in 2015, all pregnant women who had travelled to high-burden countries were screened for ZIKV. Serological and molecular tests were used to identify ZIKV-infected pregnant women. They were classified as confirmed ZIKV infection when reverse transcription (RT) PCR tested positive, or probable ZIKV infection when ZIKV immunoglobulin M and/or immunoglobulin G and ZIKV plaque reduction neutralization tests were positive. Women found positive using molecular or serological tests were prospectively followed-up with ultrasound scans and neurosonograms on a monthly basis until delivery; magnetic resonance imaging and amniotic fluid testing were performed after signed informed consent. Samples of placenta, and fetal and neonatal tissues were obtained. RESULTS: Seventy-two pregnant women tested positive for ZIKV infection: ten were confirmed by RT-PCR, and 62 were probable cases based on serological tests. The prevalence of adverse perinatal outcomes was 33.3% (three out of nine, 95% CI 12.1-64.6%): two cases of congenital ZIKV syndrome (CZS) and one miscarriage, all born to women infected in the first trimester of gestation. All ZIKV-confirmed women had persistent viraemias beyond 2 weeks (median 61.50 days; IQR 35.50-80.75). Amniotic fluid testing was only positive in the two fetuses with anomalies. CONCLUSION: The prevalence of perinatal adverse outcomes for women with ZIKV-confirmed infection was 33.3%. Amniocentesis for ZIKV RT-PCR is recommended when fetal abnormalities are found. Intensive prenatal and postnatal follow-up of ZIKV-infected pregnancies is advised in confirmed cases.

High-dose benznidazole in a 62-year-old Bolivian kidney transplant recipient with Chagas central nervous system involvement.

There is little published data on benznidazole dosing, or levels in cerebrospinal fluid. In this report, we describe the clinical course of an immunosuppressed patient with Chagas central nervous system involvement. He was treated successfully with larger benznidazole doses than are recommended, in order to reach therapeutically effective concentrations in the brain.

In utero negativization of Zika virus in a foetus with serious central nervous system abnormalities.

We describe a case of a pregnant woman with Zika virus (ZIKV) infection and a foetus with severe brain malformations. ZIKV tested positive in amniotic fluid at 19 weeks but was negative at delivery. The newborn did not meet the case definition of congenital ZIKV syndrome because neither ZIKV RNA nor IgM antibodies were detected; however, prenatal brain lesions were confirmed after birth (Graphical Abstract).

Infectious encephalitis: utility of a rational approach to aetiological diagnosis in daily clinical practice.

In this study we attempt to assess the utility of a simplified step-wise diagnostic algorithm to determinate the aetiology of encephalitis in daily clinical practice and to describe the main causes in our setting. This was a prospective cohort study of all consecutive cases of encephalitis in adult patients diagnosed between January 2010 and March 2015 at the University Hospital Vall d'Hebron in Barcelona, Spain. The aetiological study was carried out following the proposed step-wise algorithm. The proportion of aetiological diagnoses achieved in each step was analysed. Data from 97 patients with encephalitis were assessed. Following a simplified step-wise algorithm, a definite diagnosis was made in the first step in 53 patients (55 %) and in 12 additional cases (12 %) in the second step. Overall, a definite or probable aetiological diagnosis was achieved in 78 % of the cases. Herpes virus, L. monocytogenes and M. tuberculosis were the leading causative agents demonstrated, whereas less frequent aetiologies were observed, mainly in immunosuppressed patients. The overall related mortality was 13.4 %. According to our experience, the leading and treatable causes of encephalitis can be identified in a first diagnostic step with limited microbiological studies. L. monocytogenes treatment should be considered on arrival in some patients. Additional diagnostic effort should be made in immunosuppressed patients.

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.

Trypanosoma cruzi infection in a non-endemic country: epidemiological and clinical profile.

Chagas disease has been increasingly diagnosed in non-endemic countries. This is a prospective observational study performed at the Tropical Medicine Units of the International Health Program of the Catalan Health Institute, Barcelona (PROgrama de Salud Internacional del Instituto Catalán de la Salud, PROSICS Barcelona, Spain), that includes all patients with Chagas disease who attended from June 2007 to May 2012. Clinical and epidemiological data were collected. Overall, 1274 patients were included, the mean age of the patients was 37.7 years, 67.5% were women and 97% came from Bolivia. Thirteen patients had immunosuppressive conditions. The prevalence of cardiac involvement was 16.9%, lower than in previous studies performed in endemic areas (20-60%). Cardiac alterations were found in 33.8% of symptomatic and 14.1% of asymptomatic patients. The prevalence of digestive involvement was 14.8%. The rate of digestive involvement is very different among previous studies because of different diagnostic tools and strategies used. Barium enema alterations were found in 21.4% of symptomatic and 10.3% of asymptomatic patients, and oesophageal alterations were found in 3.7% of symptomatic and in 2.3% of asymptomatic patients. As shown in previous studies, Chagas disease in non-endemic countries affects younger patients and has lower morbidity.