The Renin-Angiotensin System (RAS) in COVID-19 Disease: Where We Are 3 Years after the Beginning of the Pandemic.

The RAS is a hormonal system playing a pivotal role in the control of blood pressure and electrolyte homeostasis, the alteration of which is associated with different pathologies, including acute respiratory distress syndrome (ARDS). As such, it is not surprising that a number of studies have attempted to elucidate the role and balance of the renin-angiotensin system (RAS) in COVID-19. In this review article, we will describe the evidence collected regarding the two main enzymes of the RAS (i.e., ACE and ACE2) and their principal molecular products (i.e., AngII and Ang1-7) in SARS-CoV-2 infection, with the overarching goal of drawing conclusions on their possible role as clinical markers in association with disease severity, progression, and outcome. Moreover, we will bring into the picture new experimental data regarding the systemic activity of ACE and ACE2 as well as the concentration of AngII and Ang1-7 in a cohort of 47 COVID-19 patients hospitalized at the IRCCS Sacro Cuore-Don Calabria Hospital (Negrar, Italy) between March and April 2020. Finally, we will discuss the possibility of considering this systemic pathway as a clinical marker for COVID-19.

Evaluation of the SsIR/NIE recombinant antigen ELISA for the follow up of patients infected by Strongyloides stercoralis: a diagnostic study.

Some serology assays demonstrated useful for post-treatment monitoring of Strongyloides stercoralis infection. Serology frequently has low specificity, which might be improved by the use of recombinant antigens. The Strongy Detect ELISA is based on 2 recombinant antigens (SsIR and NIE) and proved good accuracy. Aim of this study was to evaluate the performance of this test for the post-treatment monitoring of strongyloidiasis. We tested 38 paired sera, with matched fecal tests results, stored in our biobank and originating from a randomized controlled trial. At baseline, all patients tested positive for at least 1 fecal assay among PCR, direct stool microscopy and agar plate culture. Patients were re-tested with both serology and fecal assays 12 months after treatment. Primary outcome was the relative reduction in optical density (OD) between baseline and follow up. We observed that about 95% samples showed a reduction between pre and post-treatment OD, with a median relative reduction of 93.9% (IQR 77.3%­98.1%). In conclusion, the test proved reliable for post-treatment monitoring. However, some technical issues, including that the threshold for positivity has not be predefined, and that a substantial number of samples showed overflow signals, need to be fixed to permit use in routine practice.

Strongyloidiasis in humans and dogs in Southern Italy: an observational study.

Strongyloidiasis is a clinical issue both in humans and in dogs. Moreover, there are concerns about its zoonotic potential. We aimed to explore Strongyloides stercoralis epidemiology in Southern Italy in humans and dogs sharing the same environment in three different settings: (1) kennels (group K); (2) livestock farms (group L) and (3) agricultural farms (group A). For humans, a commercial ELISA test was used for screening. RT-PCR on faecal samples was done for people testing positive or equivocal at serology. On dog's faecal samples, Baermann test and RT-PCR were performed. A total of 145 dogs and 139 persons were tested. Based on faecal tests in dogs and serology in humans, a S. stercoralis positivity of 4.1% and 6.5% was revealed, respectively. The sites where cases were found were different for animals and humans. In dogs the highest positivity was in group K (6.7% against 2% and 0% in L and A). Differently, in humans the proportion of positive results was similar between the groups (p = 0.883). Fifty percent (3/6) of positive dogs were healthy; the other dogs presented weight loss and/or diarrhoea. ELISA-positive persons (n=9) were all in health, but abdominal pain (37.5%), urticaria (22.2%) and asthma (22.2%) were reported, resolving after treatment with oral ivermectin 200 µg/kg. RT-PCR performed on 13 human faecal samples resulted negative. These findings suggest that strongyloidiasis is present in humans and dogs in Southern Italy, and screening in larger cohorts would be needed for more accurate estimates.

Assessing the prevalence of Female Genital Schistosomiasis and comparing the acceptability and performance of health worker-collected and self-collected cervical-vaginal swabs using PCR testing among women in North-Western Tanzania: The ShWAB study.

BACKGROUND: Female Genital Schistosomiasis (FGS) is a neglected disease of the genital tract due to the inflammatory response to the presence of Schistosoma haematobium eggs in the genital tract. The WHO has prioritized the improvement of diagnostics for FGS and previous studies have explored the PCR-based detection of Schistosoma DNA on genital specimens, with encouraging results. This study aimed to determine the prevalence of FGS among women living in an endemic district in North-western Tanzania, using PCR on samples collected though cervical-vaginal swabs, and to compare the performance of self-collected and healthcare worker-collected (operator-collected) samples, and the acceptability of the different sampling methods. METHODS/PRINCIPAL FINDINGS: A cross-sectional study was conducted involving 211 women living in 2 villages in the Maswa district of North-western Tanzania. Urine, self-collected and operator-collected cervical-vaginal swabs were obtained from participants. A questionnaire was administered, focusing on the comfortability in undergoing different diagnostic procedures. Prevalence of urinary schistosomiasis, as assessed by eggs in urine, was 8.5% (95%CI 5.1-13.1). DNA was pre-isolated from genital swabs and transported at room temperature to Italy for molecular analysis. Prevalence of active schistosomiasis, urinary schistosomiasis, and FGS were 10.0% (95% CI 6.3-14.8), 8.5% (95%CI 5.1-13.1), and 4.7% (95%CI 2.3-8.5), respectively. When real-time PCR was performed after a pre-amplification step, the prevalence of active schistosomiasis increased to 10.4% (95%CI 6.7-15.4), and FGS to 5.2% (95%CI 2.6-9.1). Of note, more cases were detected by self-collected than operator-collected swabs. The vast majority of participants (95.3%) declared that they were comfortable/very comfortable about genital self-sampling, which was indicated as the preferred sampling method by 40.3% of participants. CONCLUSIONS/SIGNIFICANCE: The results of this study show that genital self-sampling followed by pre-amplified PCR on room temperature-stored DNA is a useful method from both technical and acceptability point of views. This encourages further studies to optimize samples processing, and identify the best operational flow to allow integration of FGS screening into women health programmes, such as HPV screening.

ELISA Test Based on the Phenolic Glycolipid-I (PGL-I) of Mycobacterium leprae: A Reality of a Laboratory from a Non-Endemic Country.

BACKGROUND: Leprosy is a neglected tropical disease caused by Mycobacterium leprae, leading to disabilities if untreated. The ELISA based on phenolic glycolipid I (PGL-I), or its synthetic version ND-O-BSA, is almost universally positive in multibacillary leprosy and thus extensively used in endemic countries. Household contacts with a positive antibody titer have ~6-fold higher probability to develop the disease than those with a negative titer. Thus, the aim of the study was to evaluate the performance of this ELISA in the setting of a non-endemic country. METHODS: We calculate the cut-off using optimized O.D. thresholds, generated by receiver operating characteristics (ROC) curve analysis, testing 39 well-characterized sera obtained from lepromatous leprosy patients with strongly positive ND-O-BSAELISA titer and 39 sera from healthy non-endemic patients never exposed to M. leprae or M. tuberculosis. Indeed, we tested a second set of sera from suspected or confirmed leprosy or household contacts (SLALT group, n=50), and patients with tuberculosis (control group, n=40). RESULTS: We detected 56.4% of SLALT and 22.5% of tuberculosis as positive, consistent with the literature. CONCLUSION: The ELISA based on ND-O-BSA may thus be considered a good option to be used in a non-endemic area as a screening tool in at risk population usually coming to our center.

Isolation and Sequencing of the First Case of Symptomatic MDR Salmonella enterica Subsp. Enterica ST40 in Human in Italy, July 2020.

Strains of drug-resistant nontyphoidal Salmonella spp. are emerging in livestock worldwide. We describe the first case of symptomatic multidrug-resistant (MDR) Salmonella enterica subsp. enterica in human and the genetic mechanisms at the basis of its antibiotic resistance. To control outbreaks, rapid identification and sequencing are necessary. Proactive research and notification are needed to evaluate the routes of transmission from livestock to humans and risk-management strategies of MDR Salmonella strains.

Regulatory T Cells as Predictors of Clinical Course in Hospitalised COVID-19 Patients.

Background: The host immune response has a prominent role in the progression and outcome of SARS-CoV-2 infection. Lymphopenia has been described as an important feature of SARS-CoV-2 infection and has been associated with severe disease manifestation. Lymphocyte dysregulation and hyper-inflammation have been shown to be associated with a more severe clinical course; however, a T cell subpopulation whose dysfunction correlate with disease progression has yet to be identify. Methods: We performed an immuno-phenotypic analysis of T cell sub-populations in peripheral blood from patients affected by different severity of COVID-19 (n=60) and undergoing a different clinical evolution. Clinical severity was established based on a modified WHO score considering both ventilation support and respiratory capacity (PaO2/FiO2 ratio). The ability of circulating cells at baseline to predict the probability of clinical aggravation was explored through multivariate regression analyses. Results: The immuno-phenotypic analysis performed by multi-colour flow cytometry confirmed that patients suffering from severe COVID-19 harboured significantly reduced circulating T cell subsets, especially for CD4+ T, Th1, and regulatory T cells. Peripheral T cells also correlated with parameters associated with disease severity, i.e., PaO2/FiO2 ratio and inflammation markers. CD4+ T cell subsets showed an important significant association with clinical evolution, with patients presenting markedly decreased regulatory T cells at baseline having a significantly higher risk of aggravation. Importantly, the combination of gender and regulatory T cells allowed distinguishing between improved and worsened patients with an area under the ROC curve (AUC) of 82%. Conclusions: The present study demonstrates the association between CD4+ T cell dysregulation and COVID-19 severity and progression. Our results support the importance of analysing baseline regulatory T cell levels, since they were revealed able to predict the clinical worsening during hospitalization. Regulatory T cells assessment soon after hospital admission could thus allow a better clinical stratification and patient management.

Antibody response induced by the BNT162b2 mRNA COVID-19 vaccine in a cohort of health-care workers, with or without prior SARS-CoV-2 infection: a prospective study.

OBJECTIVES: To assess the antibody response to BNT162b2 mRNA COVID-19 vaccine in a cohort of health-care workers (HCW), comparing individuals with previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and SARS-CoV-2-naive individuals. METHODS: HCW were tested at T0 (day of first dose), T1 (day of second dose) and T2 (2-3 weeks after second dose) for IgG anti-nucleocapsid protein, IgM anti-spike protein and IgG anti-receptor binding domain (IgG-RBD-S). The antibody response was compared between four main groups: group A, individuals with previous infection and positive antibodies at baseline; group B, individuals with the same history but negative antibodies; group C, individuals with no infection history but positive antibodies; group D, naive individuals. Repeated measures analysis was used to compare results over time-points. RESULTS: A total of 1935 HCW were included. Median IgG-RBD-S titre was significantly higher for group A (232 individuals) than for group B (56 individuals) both at T1 (A: 22 763 AU/mL, interquartile range (IQR) 14 222-37 204 AU/mL; B: 1373 AU/mL, IQR 783-3078 AU/mL, p 0.0003) and T2 (A: 30 765 AU/mL, IQR 19 841-42 813 AU/mL; B: 13 171 AU/mL, IQR 2324-22 688 AU/mL, p 0.0038) and for group D (1563 individuals; 796 AU/mL, IQR 379-1510 AU/mL at T1; 15 494 AU/mL, IQR 9122-23 916 AU/mL at T2, p < 0.0001 for both time-points). T1 values of group A were also significantly higher than T2 values of group D (p < 0.0001). Presence of symptoms, younger age and being female were associated with stronger antibody response. HCW infected in March showed a significantly stronger response (T1: 35 324 AU/mL, IQR 22 003-44 531 AU/mL; T2: 37 648 AU/mL, IQR 27 088-50 451 AU/mL) than those infected in November (T1: 18 499 AU/mL, IQR 11 492-27 283 AU/mL; T2: 23 210 AU/mL, IQR 18 074-36 086 AU/mL, p < 0.0001 for both time-points. CONCLUSIONS: Individuals with past SARS-CoV-2 infection had a strong antibody response after one single vaccine shot. A single dose might be sufficient for this group, regardless of the time elapsed since infection; however, the clinical correlation with antibody response needs to be studied.

Evaluation of Nine Commercial Serological Tests for the Diagnosis of Human Hepatic Cyst Echinococcosis and the Differential Diagnosis with Other Focal Liver Lesions: A Diagnostic Accuracy Study.

The differential diagnosis of hepatic cystic echinococcosis (CE) may be challenging. When imaging is insufficient, serology can be applied, but no consensus diagnostic algorithm exists. We evaluated the performances of nine serological tests commercialized in Europe for the diagnosis of "echinococcosis". We performed a diagnostic accuracy study using a panel of sera from patients with hepatic CE (n = 45 "liquid" content stages, n = 25 "solid" content stages) and non-CE focal liver lesions (n = 54 with "liquid" content, n = 11 with "solid" content). The diagnosis and staging of CE were based on ultrasound (gold standard). Nine commercial seroassays (5 ELISA, 2 WB, 1 Chemiluminescence Immunoassay [CLIA] and 1 Immunochromatographic test [ICT]) were the index tests. Sensitivity (Se) ranged from 43 to 94% and from 31 to 87%, and specificity (Sp) from 68 to 100% and from 94 to 100%, when borderline results were considered positive or negative, respectively. Three seroassays (2 ELISA, 1 WB) were excluded from further analyses due to poor performances. When tests were combined, Sp was 98-100%. The best results were obtained using the WB-LDBIO alone (Se 83%) or as a third test after two non-WB tests (Se 67-86%). A validated WB or two non-WB tests, read with stringent criteria (borderline = negative and considered positive only if concordant positive), possibly confirmed by the WB, appear sensible approaches.

Screening of at-risk blood donors for Chagas disease in non-endemic countries: Lessons from a 2-year experience in Tuscany, Italy.

BACKGROUND: Chagas disease (CD) is caused by the protozoan parasite Trypanosoma cruzi and is transmitted by blood-sucking triatomine insects in endemic areas of Latin America. Transmission can also occur via blood transfusion and is a major cause of CD in non-endemic areas. OBJECTIVES: The aim of the study was to assess the prevalence of anti-T. cruzi antibodies in blood donors at risk of infection in Tuscany, Italy, following the introduction of blood safety Italian legislation. MATERIAL AND METHODS: Donors (N = 1985) were tested in 2016 to 2018 for anti-T. cruzi IgG using an immunochromatographic test (ICT). Chemiluminescent immunoassay (CLIA) was performed on ICT-positive donors to exclude CD, whereas enzyme-linked immunosorbent assay and western blot were performed in case of discordant results. All assays were performed on CD patients (N = 10) for validation. RESULTS: Ten blood donors had a positive ICT result, with a resulting T. cruzi seroprevalence of 0.5% but demonstrated negative results to CLIA, as well as to the other serological assays. The comparison of serological assays suggested a lower relative sensitivity of ICT. CONCLUSION: The results of this study confirm the significance of serological testing in the screening strategy for CD. However, they provide evidence for discontinuing the use of ICT as a screening test and suggest that a sensitive, specific and multi-sample format assay should be used at the national level for uniformity of results.

Risk of transfusion-transmitted malaria: evaluation of commercial ELISA kits for the detection of anti-Plasmodium antibodies in candidate blood donors.

BACKGROUND: Transfusion with Plasmodium-infected blood represents a risk for malaria transmission, a rare but severe event. Several non-endemic countries implement a strategy for the screening of candidate blood donors including questionnaire for the identification of at-risk subjects and laboratory testing of blood samples, often serology-based, with temporary deferral from donation for individuals with a positive result. In Italy, the most recent legislation, issued in November 2015, introduced the use of serological tests for the detection of anti-Plasmodium antibodies. METHODS: In the absence of a gold standard for malaria serology, the aim of this work was to evaluate five commercial ELISA kits, and to determine their accuracy (sensitivity and specificity) in comparison to immuno-fluorescence antibody test (IFAT), and their agreement (concordance of results). Serum samples from malaria patients or from subjects with malaria history (N = 64), malaria naïve patients with other parasitic infections (N = 15), malaria naïve blood donors (N = 8) and malaria exposed candidate blood donors (N = 36) were tested. RESULTS: The specificity of all ELISA kits was 100%, while sensitivity ranged between 53 and 64% when compared to IFAT on malaria patients samples. When tested on candidate blood donors' samples, ELISA kits showed highly variable agreement (42-94%) raising the possibility that the same individual could be included or excluded from donation depending on the test in use by the transfusion centre. CONCLUSIONS: These preliminary results indicate how the lack of a gold standard for malaria serology must be taken into account in the application and future revision of current legislation. There is need of developing more sensitive serological assays. Moreover, the adoption of a unique serological test at national level is recommended, as well as the development of screening algorithms based on multiple laboratory tests, including molecular assays.

Auranofin and its Analogues Show Potent Antimicrobial Activity against Multidrug-Resistant Pathogens: Structure-Activity Relationships.

Due to the so-called "antibiotic resistance crisis" new antibacterial agents are urgently sought to treat multidrug-resistant pathogens. A group of gold- or silver-based complexes, of general formula [M(PEt3 )X] (with M=Au or Ag, and X=Cl, Br or I), alongside with three complexes bearing a positive or negative charge-[Au(PEt3 )2 ]Cl, K[Au(CN)2 ] and [Ag(PEt3 )2 ]NO3 -were prepared and comparatively tested with auranofin on a representative panel of pathogens including Gram-positive, Gram-negative and Candida strains. Interestingly, all the gold and silver complexes tested were active on Gram-positive strains, with the gold complexes having greater efficacy. The effects of the gold compounds were potentiated to a larger extent than silver compounds when tested in combination with a permeabilizing agent. A number of relevant structure-activity relationships emerged from the comparative analysis of the observed antibacterial profiles, shedding new light on the underlying molecular mechanisms of the action of these compounds.

Travelers lowering their guard: a bacterial, viral and protozoan co-infection after a five-day journey in India.

We present a case of concurrent infections by Campylobacter jejuni, Giardia intestinalis and Hepatitis E virus acquired during a 5-days travel to India by an Italian traveller : Professionals responsible for pre- and post-travel care should underline food and water precautions and prescribe an adequate diagnostic work-up in symptomatic patients.

In vitro and in vivo efficacy, toxicity, bio-distribution and resistance selection of a novel antibacterial drug candidate.

A synthetic antimicrobial peptide was identified as a possible candidate for the development of a new antibacterial drug. The peptide, SET-M33L, showed a MIC90 below 1.5 µM and 3 µM for Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively. In in vivo models of P. aeruginosa infections, the peptide and its pegylated form (SET-M33L-PEG) enabled a survival percentage of 60-80% in sepsis and lung infections when injected twice i.v. at 5 mg/Kg, and completely healed skin infections when administered topically. Plasma clearance showed different kinetics for SET-M33L and SET-M33L-PEG, the latter having greater persistence two hours after injection. Bio-distribution in organs did not show significant differences in uptake of the two peptides. Unlike colistin, SET-M33L did not select resistant mutants in bacterial cultures and also proved non genotoxic and to have much lower in vivo toxicity than antimicrobial peptides already used in clinical practice. The characterizations reported here are part of a preclinical development plan that should bring the molecule to clinical trial in the next few years.

Accuracy of funduscopy to identify true edema versus pseudoedema of the optic disc.

PURPOSE: Differential diagnosis between acute optic disc edema (ODE) and optic disc pseudoedema (PODE) may be a clinical challenge even for well-trained ophthalmologists. Funduscopy remains the first-line investigation. The aim of this study was to assess the accuracy, sensitivity, and specificity of funduscopy in differentiating ODE from PODE. METHODS: This was an observational, cross-sectional, two-center study of subjects referred for presumed acute ODE. During funduscopy, each observer completed a form concerning the presence/absence of the 10 conventional signs of ODE. Seventy-four patients with ODE and 48 subjects with PODE were included in the analysis. Accuracy, sensitivity, and specificity from all possible combinations of signs were calculated by support vector machine (SVM) analysis. RESULTS: As a single sign, the swelling of the peripapillary retinal nerve fiber layer had the highest accuracy (0.92; 95% confidence interval [CI], 0.82-0.97). Little variation was observed when more than fours signs were present. The best four-sign combinations were SWELLING, HEMORRHAGES, papilla ELEVATION, and CONGESTION of peripapillary vessels (accuracy, 0.93; 95% CI, 0.83-0.98; sensitivity, 0.95; specificity, 0.89). The presence of retinal or choroidal folds appeared to be a pathognomonic sign of true ODE (100% sensitivity) but had a low rate of presentation (23%). CONCLUSIONS: The presence of at least four ophthalmoscopic signs (with the sign "swelling" included) gives the highest accuracy. Furthermore, peripapillary retinal folds seem to be related exclusively to ODE because they were never observed in our PODE group. These data may be useful for clinicians when evaluating patients referred for presumed optic disc edema in the acute phase.

A regularization algorithm for decoding perceptual temporal profiles from fMRI data.

In several biomedical fields, researchers are faced with regression problems that can be stated as Statistical Learning problems. One example is given by decoding brain states from functional magnetic resonance imaging (fMRI) data. Recently, it has been shown that the general Statistical Learning problem can be restated as a linear inverse problem. Hence, new algorithms were proposed to solve this inverse problem in the context of Reproducing Kernel Hilbert Spaces. In this paper, we detail one iterative learning algorithm belonging to this class, called ν-method, and test its effectiveness in a between-subjects regression framework. Specifically, our goal was to predict the perceived pain intensity based on fMRI signals, during an experimental model of acute prolonged noxious stimulation. We found that, using a linear kernel, the psychophysical time profile was well reconstructed, while pain intensity was in some cases significantly over/underestimated. No substantial differences in terms of accuracy were found between the proposed approach and one of the state-of-the-art learning methods, the Support Vector Machines. Nonetheless, adopting the ν-method yielded a significant reduction in computational time, an advantage that became more evident when a relevant feature selection procedure was implemented. The ν-method can be easily extended and included in typical approaches for binary or multiple classification problems, and therefore it seems well-suited to build effective brain activity estimators.