Diagnostic performance of mycologic and serologic methods in a cohort of patients with suspected sporotrichosis

Abstract Background The gold standard for the sporotrichosis diagnosis is culture; however, serologic approaches have been recently implemented to aid in the sporotrichosis diagnosis. Nevertheless, the clinical consequences of the introduction of serologic tests are poorly addressed. Aims To correlate the results of culture and serology of patients with suspected sporotrichosis. Methods A retrospective study of 198 patients with suspected sporotrichosis was conducted. Information about culture isolation of Sporothrix from clinical samples and antibody detection by an enzyme-linked immunosorbent assay (ELISA) were obtained from the medical records of the patients. Results Positive culture and antibody detection was observed in the samples of 84 patients (42.4%). Forty-one samples (20.7%) showed negative results with both techniques and divergent results were obtained in the samples of 73 patients (36.9%). False negative results in the ELISA were observed with 23 patients (31.5%), 78.3% of them with less than 30 days of infection ( p  = 0.0045). Among the initial false positive ELISA in the sera of 50 patients, four samples in culture yielded the growth of Sporothrix , and 27 improved with itraconazole. At the end of follow-up, a diagnosis of proven or probable sporotrichosis was established in 139 patients, and possible sporotrichosis in 11 patients. The treatment of the patients with probable sporotrichosis with antifungal drugs resulted in clinical cure for these individuals. Conclusions These two techniques are complementary in the diagnosis of sporotrichosis, making diagnosis and clinical decision more precise.