Development and validation of a new quantitative reverse transcription PCR assay for the diagnosis of human sporotrichosis.

Sporotrichosis is an emergent public health problem. The mycological diagnosis of this infection is based on culture, which is fastidious and may represent a biohazard for technicians. Although not widely implemented in routine diagnosis, molecular methodologies are fast, have good accuracy, and can be easily standardized, aiding in the early diagnosis of neglected mycoses. This study aimed at implementing a new pan-Sporothrix quantitative reverse transcription PCR (RT-qPCR) assay, and then validating it on clinical samples from confirmed human sporotrichosis cases. A total of 68 human samples with culture-confirmed diagnosis of sporotrichosis were collected from 64 patients followed at a Brazilian reference center for endemic mycoses. These samples were submitted to whole nucleic acid extraction, followed by an RT-qPCR protocol. The limit of detection was 244 fg, the efficiency was 2.0 (100%), and the assay could amplify the genetic material of the three major clinically relevant species of the genus Sporothrix. Among the 68 samples analyzed, 62 were positive in RT-qPCR, showing an overall sensitivity of 91.18%, which variated according to the type of biological sample: 96.72% in skin samples (n = 61) and 100% in respiratory samples (n = 3), whereas all cerebrospinal fluid specimens (n = 4) were negative. The specificity was 100% when tested in 25 samples from patients with other mycoses and tuberculosis. In addition, DNA from 93 fungal species did not yield positive results, confirming the high specificity of this test. Our RT-qPCR presented high sensitivity and specificity, representing an excellent tool for a fast and reliable diagnosis of human sporotrichosis.

Sporotrichosis is a deep mycosis with limited laboratorial techniques for fast diagnosis. We developed an assay able to detect the genetic material of fungal agents of sporotrichosis, and validated it in human specimens from patients with this disease, obtaining high positivity and specificity.

Zoonotic sporotrichosis in renal transplant recipients from Rio de Janeiro, Brazil.

Sporotrichosis is the main subcutaneous mycosis in the world. In the last two decades, zoonotic sporotrichosis transmitted by cats has become hyperendemic in Rio de Janeiro, Brazil. Renal transplant recipients are subject to invasive fungal infection because of the effects of immunosuppressive therapy, but sporotrichosis is rarely reported. The authors conducted a retrospective study describing epidemiological, clinical, and therapeutic data related to adult renal-transplant-recipient patients diagnosed with sporotrichosis. The molecular identification of fungal isolates was performed. Minimal inhibitory concentration (MIC) of amphotericin B (AMB), itraconazole (ITZ), posaconazole (POS), isavuconazole, and terbinafine (TRB) against the strains was determined using the protocol described by the Clinical and Laboratory Standards Institute (CLSI). Six cases were identified from a cohort with 2429 sporotrichosis patients. They were five men and one woman, with a mean age of 44.2 years (range: 34-54 years). Four of them had cutaneous limited forms, and two patients had disseminated forms. The mean time between transplant and the onset of sporotrichosis symptoms was 25.5 (range: 6-36) months. Sporothrix brasiliensis was identified as the causative agent. The isolates were classified as wild type for all antifungal drugs tested. Treatment schemes included AMB (deoxycholate and liposomal), ITZ, and TRB. Five patients evolved to cure, and one died as a result of disseminated disease. Renal transplant recipients may be a vulnerable group for sporotrichosis in endemic countries. The authors highlight the importance of sporotrichosis prevention, early diagnosis, and treatment to prevent disseminated disease and poor prognosis.

Paracoccidioidomycosis after Highway Construction, Rio de Janeiro, Brazil.

Transmission of Paracoccidioides spp. fungi to humans is usually related to manipulation of soil. Rural workers are the most affected group. We report an outbreak of paracoccidioidomycosis after deforestation and massive earth removal during construction of a highway in Rio de Janeiro, Brazil. Extensive environmental disturbances might be involved in fungal transmission.