Cerebrospinal fluid PCR: A new approach for the diagnosis of CNS sporotrichosis

Clinical characteristics, diagnosis, and treatment of central nervous system sporotrichosis: Systematic review and meta-analysis

BACKGROUND

The clinical features of central nervous system (CNS) sporotrichosis are derived from case reports and a limited series of cases. Our objective was to carry out a systematic review and meta-analysis of CNS sporotrichosis.

METHODS

We searched PubMed/MEDLINE, Embase, Scopus, and LILACS on 9 September 2023. Our inclusion criteria were documentation of Sporothrix and demonstrated CNS involvement. A metaproportion or metamean analysis was performed to estimate a summary proportion with 95% confidence intervals.

RESULTS

We included 52 cases of CNS sporotrichosis published from 1966 to 2023. Forty-six patients were male (88%, 95% CI: 77-95), and the mean age was 39 years (95% CI: 36-43). Close contact with cats was reported in 55% of cases (95% CI: 37-72). Thirty-two (61.5%) patients were from Brazil, 18 patients from the United State of America (34.6%). Only two Sporothrix species were reported: S. schenckii (26/41, 63%), and S. brasiliensis (15/41, 37%). The most common neurological symptom was headache. Meningitis was chronic in approximately 80% of cases. A significant majority of the patients were immunocompromised. HIV infection was the primary cause of immunosuppression (85%, 95% CI: 61-95). Overall mortality was 56% (22/39). The comparison of Kaplan-Meier survival curve showed a higher mortality with a statistically significant difference in immunosuppressed patients (p = .019).

CONCLUSION

CNS sporotrichosis represents a notable cause of chronic meningitis, especially in individuals living in the Americas with HIV infection and concurrent skin lesions.

Evaluation of Five Non-Culture-Based Methods for the Diagnosis of Meningeal Sporotrichosis

Sporotrichosis is the main subcutaneous mycosis worldwide. Several complications, including meningeal forms, can be observed in immunocompromised individuals. The sporotrichosis diagnosis is time-consuming due to the culture's limitations. The low fungal burden in cerebrospinal fluid (CSF) samples is another important drawback in the diagnosis of meningeal sporotrichosis. Molecular and immunological tests can improve the detection of Sporothrix spp. in clinical specimens. Therefore, the following five non-culture-based methods were evaluated for the detection of Sporothrix spp. in 30 CSF samples: (i) species-specific polymerase chain reaction (PCR); (ii) nested PCR; (iii) quantitative PCR; (iv) enzyme-linked immunosorbent assay (ELISA) for IgG detection; and (v) ELISA for IgM detection. The species-specific PCR was unsuccessful in the diagnosis of the meningeal sporotrichosis. The other four methods presented substantial levels of sensitivity (78.6% to 92.9%) and specificity (75% to 100%) for the indirect detection of Sporothrix spp. Both DNA-based methods presented similar accuracy (84.6%). Both ELISA methods were concomitantly positive only for patients with sporotrichosis and clinical signs of meningitis. We suggest that these methods should be implemented in clinical practice to detect Sporothrix spp. in CSF early, which may optimize treatment, augment the chances of a cure, and improve the prognosis of affected individuals.

Meningeal Sporotrichosis Due to Sporothrix brasiliensis: A 21-Year Cohort Study from a Brazilian Reference Center

Meningeal sporotrichosis is rare and occurs predominantly in immunosuppressed individuals. This retrospective study explored clinical and laboratory characteristics, treatment, and prognosis of patients with disseminated sporotrichosis who underwent lumbar puncture (LP) at a Brazilian reference center from 1999 to 2020. Kaplan-Meier and Cox regression models were used to estimate overall survival and hazard ratios. Among 57 enrolled patients, 17 had meningitis. Fifteen (88.2%) had HIV infection, and in 6 of them, neurological manifestations occurred because of the immune reconstitution inflammatory syndrome (IRIS). The most frequent symptom was headache (88.2%). Meningeal symptoms at first LP were absent in 7/17 (41.2%) patients. Sporothrix was diagnosed in cerebrospinal fluid either by culture or by polymerase chain reaction in seven and four patients, respectively. All but one patient received prolonged courses of amphotericin B formulations, and seven received posaconazole, but relapses were frequent. Lethality among patients with meningitis was 64.7%, with a higher chance of death compared to those without meningitis (HR = 3.87; IC95% = 1.23;12.17). Meningeal sporotrichosis occurs mostly in people with HIV and can be associated with IRIS. Screening LP is indicated in patients with disseminated disease despite the absence of neurological complaints. Meningitis is associated with poor prognosis, and better treatment strategies are needed.

Beyond Domestic Cats: Environmental Detection of Sporothrix brasiliensis DNA in a Hyperendemic Area of Sporotrichosis in Rio de Janeiro State, Brazil

In Brazil, sporotrichosis has transitioned from a rural to urban disease, driven by a shift in the initiation of infection from the accidental inoculation of organic matter to the traumatic implantation of the fungus by cats. Since the emergence of zoonotic sporotrichosis caused by Sporothrix brasiliensis, investigations have largely ignored the environmental habitat of the pathogen due to its association with domestic cats. Therefore, we investigated 18 environmental samples collected from rural areas of two cities where zoonotic sporotrichosis is endemic, but where domestic cats are scarce. We utilized traditional culture methods, and samples were also examined with two molecular methods used for the clinical diagnosis of sporotrichosis: a nested-PCR targeting the ITS region and a species-specific PCR targeting the calmodulin gene. No Sporothrix colonies were identified by traditional culture methods. However, the nested-PCR and the species-specific PCR for S. brasiliensis were positive for 18 and 5 samples, respectively. Sequencing revealed that positive results with the nested-PCR were due to non-specific amplification of other Ophiostomatales DNA, rather than Sporothrix spp. Three of the five amplicons from the species-specific PCR were suitable for sequencing and confirmed the presence of S. brasiliensis DNA. Hence, we confirmed that S. brasiliensis, as with other Sporothrix species, has an environmental habitat. Our findings underscore the challenges of nested-PCR for Sporothrix environmental studies and highlight that sequencing must follow PCR protocols to definitively identify Sporothrix spp. in environmental samples.

Nested PCR for the Diagnosis of Feline Sporotrichosis From Formalin-Fixed and Paraffin-Embedded Samples Using Different DNA Extraction Protocols

Sporotrichosis is a chronic, cosmopolitan granulomatous mycosis that affects humans and animals. The infection is caused by the dimorphic fungi Sporothrix sp. The aims of the present study were to evaluate, standardize and validate a nested PCR technique using two DNA purification kits for the extraction of DNA from formalin fixed and paraffin-embedded tissues (FFPE) for Sporothrix sp. detection. FFPE mycological culture pellet samples of different Sporothrix species (S. chilensis, S. mexicana, S. pallida, S. globosa, S. brasiliensis and S. schenckii) were used as positive controls and clinical FFPE tissue samples of animals positive for Cryptococcus sp., Leishmania infantum and Histoplasma sp. were used as negative controls. Ten clinical FFPE skin samples from cats with sporotrichosis were used to validate the nested PCR. These samples were cut into two distinct paraffin sectioning protocols (5 and 16 μm thick). The paraffin sections were subjected to two different DNA extraction kits (chemical and thermal extractions). A nested PCR was performed on the extracted DNA to identify the genus Sporothrix. The chemical extraction protocol with the 5 μm thick paraffin section was more effective in extracting DNA from Sporothrix sp. from FFPE samples and the nested PCR technique showed the highest sensitivities (100% in the positive controls and of 50% in the skin samples of cats) and specificity (100%). Therefore, the nested PCR using this protocol has great potential to be applied in Sporothrix sp. diagnosis in FFPE samples of cats.

The Historical Burden of Sporotrichosis in Brazil: a Systematic Review of Cases Reported from 1907 to 2020

Sporotrichosis is a cosmopolitan subcutaneous mycosis caused by Sporothrix species. Recently, this mycosis has gained notoriety due to the appearance of new endemic areas, recognition of new pathogenic species, changes in epidemiology, occurrence of outbreaks, and increasing numbers of cases. The purpose of this study is to analyze the peculiarities of sporotrichosis cases in Brazil since its first report in the country until 2020. In this work, ecological, epidemiological, clinical, and laboratorial characteristics were compiled. A systematic review of human sporotrichosis diagnosed in Brazil and published up to December 2020 was performed on PubMed/MEDLINE, SciELO, Web of Science, and LILACS databases. Furthermore, animal sporotrichosis and environmental isolation of Sporothrix spp. in Brazil were also evaluated. The study included 230 papers, resulting in 10,400 human patients. Their ages ranged from 5 months to 92 years old and 55.98% were female. The lymphocutaneous form was predominant (56.14%), but systemic involvement was also notably reported (14.34%), especially in the lungs. Besides, hypersensitivity manifestations (4.55%) were described. Most patients had the diagnosis confirmed by isolation of Sporothrix spp., mainly from skin samples. Sporothrix brasiliensis was the major agent identified. HIV infection, cardiovascular diseases, and diabetes were the most common comorbidities. Cure rate was 85.83%. Concerning animal sporotrichosis, 8538 cases were reported, mostly in cats (90.77%). Moreover, 13 Sporothrix spp. environmental strains were reported. This review highlights the burden of the emergent zoonotic sporotrichosis in Brazil, reinforcing the importance of "One Health" based actions to help controlling this disease.