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Comparison of two in vitro antifungal sensitivity tests and monitoring during therapy of Sporothrix schenckii sensu stricto in Malaysian cats
Author(s) -
Han Hock Siew,
Kano Rui,
Chen Charles,
Noli Chiara
Publication year - 2017
Publication title -
veterinary dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.744
H-Index - 60
eISSN - 1365-3164
pISSN - 0959-4493
DOI - 10.1111/vde.12417
Subject(s) - itraconazole , ketoconazole , posaconazole , fluconazole , sporothrix schenckii , azole , terbinafine , amphotericin b , microbiology and biotechnology , antifungal , biology , veterinary medicine , medicine , sporotrichosis , pharmacology , immunology
Background Feline sporotrichosis is common in Malaysia. Thermosensitivity and effects of azole treatment on fungal susceptibility are unknown. Objectives To evaluate thermotolerance and antifungal susceptibility of feline Malaysian Sporothrix isolates , compare microdilution ( MD ) and E‐test results, and investigate changes in susceptibility during azole therapy. Methods Sporothrix schenckii sensu stricto was isolated from 44 cats. Thermotolerance was determined via culture at 37°C for 7 days. Susceptibility to itraconazole ( ITZ ), ketoconazole ( KTZ ) and terbinafine ( TRB ) was assessed in 40 isolates by MD ; to amphotericin B ( AMB ), KTZ , ITZ , fluconazole (FLC) and posaconazole (POS) by E‐test. Results were statistically compared by Pearson's Product Moment. In eight ketoconazole treated cats, susceptibility testing to itraconazole and ketoconazole was repeated every two months for six months. Results Thermotolerance was observed in 36 of 44 (82%) isolates. Assuming that isolates growing at antifungal concentrations ≥4 mg/mL were resistant, all were resistant on E‐test to FLC and AMB , 11 (28%) to POS , 6 (15%) to ITZ and 1 (3%) to KTZ . On MD , 27 of 40 (68%) were resistant to TRB , 2 (5%) to ITZ and 3 (8%) to KTZ . There was no correlation between E‐test and MD results ( KTZ r = 0.10, P = 0.54, and ITZ r = 0.11, P = 0.48). MD values for ITZ and KTZ did not exceed 4 mg/L during KTZ therapy. Conclusion The majority of feline isolates in Malaysia are thermosensitive. Lack of correlation between E‐test and MD suggests that the E‐test is unreliable to test antifungal susceptibility for Sporothrix spp. compared to MD . KTZ was the antifungal drug with the lowest MIC . Prolonged KTZ administration may not induce changes in antifungal susceptibility.