In vitro susceptibility pattern of Sporothrix schenckii strains isolated from three centers in India

Background & objectives: With the availability of more number of antifungal agents in recent years, drugs other than saturated solution of potassium iodide (SSKI) are being increasingly used to treat sporotrichosis. It was therefore considered pertinent to evaluate in vitro antifungal susceptibility pattern of Sporothrix schenckii strains isolated at three centers in India against five commonly used antifungal agents. Methods: Agar dilution method was used to evaluate 50 clinical isolates (25 from north, 17 from cast and 8 from south India) both in its yeast and mycelial forms against amphotericin-B, 5-fluorocytosine, ketoconazole, fluconazole and itraconazole. Results: No resistance was observed in the yeast form of S, schenckii against amphotericin B and azoles. However, 54 per cent strains in the yeast form were resistant to 5-fluorocytosine. None of the strains was susceptible to amphotericin B and ketoconazole, 56 and 10 per cent strains in the mycelial form were susceptible to itraconazole and fluconazole respectively. No significant difference was observed in the antifungal susceptibility pattern among the strains isolated from these three regions in India. Interpretation & conclusion: Clinical isolates of S schenckii from three regions of India had a more or less uniform antifungal susceptibility pattern. Itraconazole had the best in vitro susceptibility results against the clinical isolates of S schenckii and has the potential to replace SSKI.