Evaluation of targets for Strongyloides genus specific molecular diagnosis in experimental strongyloidiasis.

Strongyloides venezuelensis has been used in different experimental studies, such as those aimed at the evaluation of diagnostic techniques for human strongyloidiasis, mainly the molecular diagnosis. In this study, three regions (genus, 18S and 28S targets) of Strongyloides ribosomal DNA were evaluated for the molecular diagnosis of experimental strongyloidiasis. Rats were infected subcutaneously with 400 or 4000 S. venezuelensis infective larvae (400iL3 and 4000iL3), and kept for 35 days. Fecal samples were collected daily to count eggs per gram of feces (EPG) and to perform the polymerase chain reaction (PCR). Egg count started on the 5th day post-infection (pi) and ended on days 33 and 34 pi, in 400iL3 and 4000iL3 groups, respectively. Based in EPG, fecal samples were selected from days 2, 5, 8, 11, 15, 23 and 35 pi for DNA extraction; PCR (genus, 18S and 28S); and sequencing. The PCR-28S products showed higher values of identity (95-100%) in the database with the Strongyloides sequences. Therefore, it is possible to reinforce the application of PCR-28S in the diagnosis of experimental and human strongyloidiasis.

Subtypes of Blastocystis sp. isolated in fecal samples from transplant candidates in São Paulo, Brazil.

Blastocystis sp. is an intestinal protozoan commonly found in fecal samples of many animal species, including humans, but poorly studied in transplant candidates. The aim of this study was to evaluate the occurrence and molecular identification of Blastocystis sp. in fecal samples from transplant candidates. A polymerase chain reaction was performed using specific primers for Blastocystis ribosomal DNA. The DNA sequences obtained were aligned and compared with other sequences from the GenBank and MLST databases. The analyzed samples showed a positivity of 16% (24 of 150) for Blastocystis sp. The highest occurrence was observed in renal transplant candidates (31.4%), followed by hepatic transplant candidates (10.4%) and candidates for bone marrow transplantation (5.9%). Subtype (ST) 3 (45.8%) was the most prevalent among the isolates, followed by ST1 (37.5%), ST2 (12.5%), and ST7 (4.2%). This is the first study of molecular identification Blastocystis sp. in transplant candidates. Our results confirmed that ST3 was the most common subtype in transplant candidates and reinforce the importance of new studies to investigate of Blastocystis sp. in these patients.

Shotgun proteomics of Strongyloides venezuelensis infective third stage larvae: Insights into host-parasite interaction and novel targets for diagnostics.

Strongyloides venezuelensis is an important alternative source of antigen for the serologic diagnosis of human strongyloidiasis. Proteomics techniques applied to the analysis of the protein content of infective third stage larvae (iL3) of S. venezuelensis provide a powerful tool for the discovery of new candidates for immunodiagnosis. This study presents an overview of the protein iL3 S. venezuelensis focusing on the diagnosis of strongyloidiasis. A total of 877 proteins were identified by shotgun proteomics. Many of these proteins are involved in different cellular processes, metabolic as well as structural maintenance. Our results point to a catalog of possible diagnostic targets for human strongyloidiasis and highlight the need for evaluation of uncharacterized proteins, especially the proteins within the CAP domain, transthyretin, and BTPI inhibitor domains, as a repertoire as yet unexplored in the context of strongyloidiasis diagnostic markers. We believe that the protein profile presented in this shotgun analysis extends our understanding of the protein composition within the Strongyloides genus, opening up new perspectives for research on biomarkers that may help with the diagnosis of human strongyloidiasis. Data are available via ProteomeXchange with identifier PXD013703.

Screening of Strongyloides infection using an ELISA test in transplant candidates.

OBJECTIVES: Hyperinfection or disseminated strongyloidiasis has been frequently reported after transplants and is related to high mortality. This study aimed to screen for strongyloidiasis using serological diagnoses in transplant candidates. METHODS: An ELISA test was performed with filariform larvae of Strongyloides venezuelensis as a source of antigen. RESULTS: In the serum from transplant candidates, anti-Strongyloides IgG antibodies were detected in 35/150 (23.3%) samples by soluble fractions in phosphate buffered saline (PBS), 31/150 (20.7%) samples by soluble fractions in Tris-HCl, 27/150 (18.0%) samples by membrane fractions in PBS and 22/150 (14.7%) samples by membrane fractions in Tris-HCl. CONCLUSIONS: The present results suggest the ELISA test, ideally using soluble fractions of filariform larvae S. venezuelensis in PBS, as an additional strategy for the diagnosis of strongyloidiasis in transplant candidates.

Screening of Strongyloides infection using an ELISA test in transplant candidates

OBJECTIVES: Hyperinfection or disseminated strongyloidiasis has been frequently reported after transplants and is related to high mortality. This study aimed to screen for strongyloidiasis using serological diagnoses in transplant candidates. METHODS: An ELISA test was performed with filariform larvae of Strongyloides venezuelensis as a source of antigen. RESULTS: In the serum from transplant candidates, anti-Strongyloides IgG antibodies were detected in 35/150 (23.3%) samples by soluble fractions in phosphate buffered saline (PBS), 31/150 (20.7%) samples by soluble fractions in Tris-HCl, 27/150 (18.0%) samples by membrane fractions in PBS and 22/150 (14.7%) samples by membrane fractions in Tris-HCl. CONCLUSIONS: The present results suggest the ELISA test, ideally using soluble fractions of filariform larvae S. venezuelensis in PBS, as an additional strategy for the diagnosis of strongyloidiasis in transplant candidates.

Molecular diagnosis of Strongyloides stercoralis among transplant candidates.

Strongyloidiasis can occur without any symptoms or as a potentially fatal hyperinfection or disseminated infection, principally in immunosuppressed patients. Our study aimed to evaluate the application of conventional polymerase chain reaction (cPCR) and real-time PCR (qPCR). Polymerase chain reaction (PCR) and real-time PCR (qPCR) targeting the 18S rRNA gene for detection of Strongyloides stercoralis infection among transplant candidates were applied in stool samples obtained from 150 transplant candidates, preliminarily analyzed by parasitological methods. S. stercoralis larvae were visualized in 15/150 (10.0%) transplant candidates by parasitological methods. DNA from S. stercoralis was amplified in 26/150 (17.3%) and 49/150 (32.7%) stool samples of transplant candidates, using cPCR and qPCR, respectively. The results suggest that molecular methods, especially qPCR, should be used as an additional tool for diagnostic of S. stercoralis infection among transplant candidates.

Treatment of severe forms of paracoccidioidomycosis: is there a role for corticosteroids?

Despite their immunosuppressive effects, corticosteroids have long been used as adjunct therapy (aCST) in the treatment of infectious diseases. The rationale is that in certain infections it is necessary to decrease the exacerbated host's inflammatory response, which can otherwise result in tissue damage and organ dysfunction. In fact, a major concern in treating paracoccidioidomycosis (PCM) is the host's intense inflammatory response to Paracoccidioides brasiliensis, which can be further intensified by antifungal therapy. Depending on its localization, this immunological phenomenon may be life threatening or result in permanent sequels, as is the case for some patients with cerebral or laryngeal involvement. However, the literature on aCST in paracoccidioidomycosis treatment is scarce and as a result we present our recent experience in the management of four patients with severe PCM manifestations, i.e., cerebral paracoccidioidal granuloma, laryngeal stenosis, compressive abdominal mass, and exacerbated inflammatory response with tissue destruction. In addition to the antifungal therapy, these patients required aCST, which probably promoted their clinical improvement and/or prevented serious complications. We suggest that aCST: (a) can potentially help in the management of selected cases of severe forms of PCM, particularly when there is a risk of acute complications, and (b) that it can be used safely provided that the risk-benefit ratio is carefully weighed. Well-controlled, prospective studies of aCST in the treatment of severe cases of paracoccidioidomycosis are needed to better define its role in the management of PCM.

Paradoxical reaction to treatment in 2 patients with severe acute paracoccidioidomycosis: a previously unreported complication and its management with corticosteroids.

Paradoxical reactions have never been described in patients with paracoccidioidomycosis or other deep endemic mycoses out of the context of human immunodeficiency virus infection. We describe 2 patients with an acute form of paracoccidioidomycosis who presented with a worsening of their clinical manifestations while on appropriate antifungal treatment. These manifestations were severe and required adjunct corticosteroid therapy.