Use of sera cell free DNA (cfDNA) and exovesicle-DNA for the molecular diagnosis of chronic Chagas disease.

Chagas disease, a neglected tropical disease, is now considered a worldwide health concern as a result of migratory movements from Central and South America to other regions that were considered free of the disease, and where the epidemiological risk is limited to transplacental transmission or blood or organ donations from infected persons. Parasite detection in chronically ill patients is restricted to serological tests that only determine infection by previous infection and not the presence of the parasite, especially in patients undergoing treatment evaluation or in newborns. We have evaluated the use of nucleic acids from both circulating exovesicles and cell-free DNA (cfDNA) from 50 samples twice randomly selected from a total of 448 serum samples from immunologically diagnosed patients in whom the presence of the parasite was confirmed by nested PCR on amplicons resulting from amplification with kinetoplastid DNA-specific primers 121F-122R. Six samples were randomly selected to quantify the limit of detection by qPCR in serum exovesicles. When the nucleic acids thus purified were assayed as a template and amplified with kinetoplastid DNA and nuclear satellite DNA primers, a 100% positivity rate was obtained for all positive samples assayed with kDNA-specific primers and 96% when SAT primers were used. However, isolation of cfDNA for Trypanosoma cruzi and amplification with SAT also showed 100% positivity. The results demonstrate that serum exovesicles contain DNA of mitochondrial and nuclear origin, which can be considered a mixed population of exovesicles of parasitic origin. The results obtained with serum samples prove that both cfDNA and Exovesicle DNA can be used to confirm parasitaemia in chronically ill patients or in samples where it is necessary to demonstrate the active presence of the parasite. The results confirm for the first time the existence of exovesicles of mitochondrial origin of the parasite in the serum of those affected by Chagas disease.

Cutaneous and mucocutaneous leishmaniasis: experience of a Mediterranean hospital.

BACKGROUND: Leishmaniasis, considered by the World Health Organization as one of the most important tropical diseases, is endemic in the Mediterranean Basin. The aim of this study was to evaluate epidemiological and clinical characteristics of cutaneous (CL) and mucocutaneous leishmaniasis (MCL) in La Fe University Hospital, Valencia, Spain. The particular focus was on diagnosis techniques and clinical differences according to the immunological status of the patients. METHODS: An eleven-year retrospective observational study of CL and MCL episodes at the hospital was performed. Epidemiological, clinical and therapeutic variables of each case, together with the microbiological and anatomopathological diagnosis, were analyzed. RESULTS: A total of 42 patients were included, 30 of them were male and 28 were immunocompetent. Most of the cases (36/42) were diagnosed in the last 5 years (2013-2017). The incidence of CL and MCL increased from 3.6/100,000 (2006-2012) to 13.58/100,000 (2013-2017). The majority of the patients (37/42) exhibited CL, in 30 cases as single lesions (30/37). Ulcerative lesions were more common in immunosuppressed patients (13/14) than in immunocompetent patients (20/28), (P = 0.2302). The length of lesion presence before diagnosis was 7.36 ± 6.72 months in immunocompetent patients and 8.79 ± 6.9 months in immunosuppressed patients (P = 0.1863). Leishmania DNA detection (92.3%) was the most sensitive diagnostic technique followed by Giemsa stain (65%) and histopathological examination (53.8%). Twelve patients (12/42) had close contact with dogs or were living near to kennels, and 10 of them did not present underlying conditions. Intralesional glucantime (21/42) and liposomal amphotericin B (7/42) were the most common treatments administered in monotherapy. All patients evolved successfully and no relapse was reported. CONCLUSIONS: Some interesting clinical and epidemiological differences were found in our series between immunocompetent and immunosuppressed patients. Future studies can take these results further especially by studying patients with biological therapy. Skin biopsies combining NAAT with histological techniques are the most productive techniques for CL or MCL diagnosis.

Nosocomial fungemia by Candida auris: First four reported cases in continental Europe.

BACKGROUND: Candida auris is an emerging multidrug-resistant yeast that can cause invasive infections and is associated with high mortality. It is typically resistant to fluconazole and voriconazole and, some cases, also to echinocandins and amphotericin B. This species, phylogenetically related to Candida haemulonii, is frequently misidentified by commercial identification techniques in clinical laboratories; therefore, the real prevalence of C. auris infections may be underestimated. AIMS: To describe the clinical and microbiological features of the first four cases of C. auris fungemia episodes observed in the European continent. METHODS: The four patients were hospitalized in the adult surgical intensive care unit. A total of 8 isolates (two per patient) from blood and catheter tip were analyzed. RESULTS: All isolates were misidentified as Saccharomyces cerevisiae by AuxaColor 2, and as Candida sake by API ID20C. VITEK MS technology misidentified one isolate as Candida lusitaniae, another as C. haemulonii and could not identify the other six. C. auris identification was confirmed by ITS rDNA sequencing. All isolates were fluconazole (MIC >256mg/l) and voriconazole (MIC 2mg/l) resistant and susceptible to posaconazole, itraconazole, echinocandins and amphotericin B. CONCLUSIONS: C. auris should be regarded as an emerging pathogen, which requires molecular methods for definitive identification. Our isolates were highly resistant to fluconazole and resistant to voriconazole, but susceptible to the other antifungals tested, which emphasizes the importance of accurately identifying this species to avoid therapeutic failures.