SPECIES-SPECIFIC PCR FOR THE DIAGNOSIS OF SPOROTRICHOSIS CAUSED BY SPOROTHRIX BRASILIENSIS

Abstract

Despite thousands of sporotrichosis cases related to the zoonotic transmission of Sporothrix brasiliensis have been described, the diagnostic gold standard is still the classical culturing methods. The mycological culture results are available after
seven to 30 days of incubation. Since an early diagnosis contributes to improving the
treatment and to the spread control of this mycosis, studies evaluating faster diagnostic
methods are needed. Therefore, we aimed to evaluate the species-specific PCR for the
sporotrichosis diagnosis caused by S. brasiliensis, using samples collected with a noninvasive technique. Seventy-four swabs from feline (n=64), canine (n=5), and human
(n=5) suspect sporotrichosis cases were included. All samples were submitted to classical
methods for diagnosis and to S. brasiliensis-specific PCR. Using mycological culture as
the gold standard, the diagnosis of S. brasiliensis-caused infection was confirmed in 69%
(51/74) of the cases. PCR was positive in 30 out of these 51 cases, showing 59%
sensitivity, 100% specificity, 72% accuracy, 100% positive predictive value, and 52%
negative predictive value. Consequently, more studies are needed to elucidate the
interference factors that culminated with the high rate of false-negative results and then
optimize this molecular test for the accurate diagnosis of infections caused by S.
brasiliensis.