Sporotrichosis study in domestic cats in the city of Guarulhos, São Paulo

Author(s)

Fernanda Fidelis Gonsales

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2018-05-16

Examining board members

Nilson Roberti Benites; Benedito Correa; Isabella Dib Ferreira Gremião; Anderson Messias Rodrigues; Anna Catharina Maia Del Guercio von Sydow

• Advisor: Nilson Roberti Benites

Abstract

Sporotrichosis is a zoonotic mycosis that affects urban centers in Brazil. The cat plays key role in the fungal transmission of this disease. In the last 3 years, the city of Guarulhos has registered more than 1500 cases in cats and this situation received a status of compulsory notification. The objective of the present work was to analyze the epidemiology from the strains of Sporothrix schenckii complex in relation to the phenotypic, molecular and drug susceptibility aspects of isolated samples collected in cats from Guarulhos city (São Paulo). The study was divided in two experiments: the first one consisting of 119 cats divided into three groups: Case, Contacting and Non-Contacting. Samples were obtained by swab lesions from the cats of Case group and from the other oral swab groups and submitted to mycological culture; at the same time, samples were obtained for cytology processing in liquid medium by cell block (CB). The isolated samples were submitted to PCR for species identification, as well the drug sensibility tests - microdilution and E-Test. During the process, 25 cats were euthanized and skin and organ samples were submitted to histopathological and immunohistochemical analysis. The second study was made with 135 cats divided into two groups: Symptomatic and Asymptomatic. The obtained samples were processed for mycological culture and PCR, but this time PCR was performed directly from the lesion and not after fungal isolation. This study obtained 92.31% of positivity among the cats with suspected of sporotrichosis in mycological culture. In this project, 100% of the samples were identified as S. brasiliensis. The proposed technique of cytology in liquid medium by cell block (CB) presented 93% of positivity for Sporothrix spp, with sensitivity of 97.50% between fungal isolation and 94.87% for immunocytochemistry. In conclusion, CB may be a good option for public health diagnosis. Investigations about the susceptibility of the isolates to the drugs: terbinafine, amphotericin B, itraconazole, fluconazole and voriconazole were 0.06 - 0.5 µg/ml, 0.002 - 2 µg/mL and 0.023 -> 32 µg/mL, > 256 µg/mL and 1-8 µg/mL, respectively. Samples submitted to histopathology and immunhistochemistry pointed the presence of Sporothrix spp on the skin, mesenteric lymph node, spleen, liver, lung and heart. No fungal element was observed in the kidney. There was no relationship between inflammatory infiltrate intensity and Sporothrix intensity in the skin. It is concluded that the PCR performed directly from the lesion can be used in areas with a high disease frequency, since the diagnostic sensitivity was 90.20%, but the specificity was 42.11%. Thus, in areas of low frequency of sporotrichosis, it is recommended to use the gold standard, which is the mycological culture for Sporothrix spp research, and to perform the PCR for samples whose isolation is obtained. The variables of lesions type and beginning of the treatment interfere in the diagnostic result of direct PCR of the lesion. (AU)

• FAPESP's process: 16/16023-8 - Study of sporotrichosis in cats in Guarulhos city, state of São Paulo
• Grantee: Fernanda Fidelis Gonsales
• Support Opportunities: Scholarships in Brazil - Doctorate