Abstract:
Tinea capitis(TC) or dermatophytosis is a superficial fungal infection of hair of the head/scalp referred as scalp ringworm that can be difficult to cure at times. Emerging fungal pathogens are becoming resistant to antifungal drugs, potentiating the possibility of new fungal infections. Fungal biofilms are a growing clinical concern associated with antifungal resistance and high mortality rates in Tinea capitis patients.The objective was to investigate the physiological responses of Trichophyton mentagrophyte isolates which lead them to be resistant against antifungals. Moreover, study also focused to determine fungal virulent attributes of biofilm, protease and phospholipase enzymes under the physiological stress responses. Study has been focused on two T. mentagrophyte isolates previously reported as potential SQLE gene mutants that shown resistance against commonly available antifungals. Study investigated the antifungal drug susceptibility testing of potential T. mentagrophyte isolates from Tinea capitis against Terbinafine, Ketoconazole and Fluconazole. Potential fungal isolates of Tinea capitis were further studied for in vitro biofilm formation and effect of antifungal agents on biofilm as well as fungal enzymes protease and phospholipase was focused. In vitro qualitative and quantitative approaches were used to evaluate biofilm formation including the test tube method, tissue culture plate method in addition to staining with crystal violet and safranin. Further, the influences of varying pH, osmotic and oxidative stresses on fungal growth and biofilm formation were also studied. The antifungal drug susceptibility revealed that both isolates were sensitive to Terbinafine and Ketoconazole, however resistant against Fluconazole. MIC50 values of fungal planktonic cells obtained were as (0.08µg/ml) for Terbinafine, (2µg/ml) for Ketoconazole and (16µg/ml) for Fluconazole. T. mentagrophyte isolates growth was promoted at a concentration of 5mM H202 and at 2M NaCl concentration. However, fungal growth was suppressed at higher physiological stress concentrations of H202 and NaCl. The isolates showed maximum growth at pH 5. Study evaluated that Tm25 and Tm26 were able to form biofilm. Maximum biofilm formation was at neutral pH. Oxidative and osmotic stress at the concentration of 5mM H202 and on 2M NaCl showed maximum biofilm formation for both isolates. MIC50 values of biofilm cells obtained were (0.16µg/ml) for Terbinafine, (4µg/ml) for Ketoconazole and (32µg/ml) for Fluconazole. Tm25 and Tm26 were able to produce protease and phospholipase enzyme. The isolates showed maximum protease activity at slightly acidic pH 5, while the enzyme production was inhibited at highly acidic pH. Terbinafine had the significant inhibitory effect on the production of protease, phospholipase and biofilm followed by Ketoconazole due to loss of fungal growth in both isolates.Finally, it is concluded that SQLE gene mutant Tm 25 and Tm 26 showed resistance against Fluconazole due to moderate adaptation to osmotic and oxidative stresses, which also suppress fungal virulent enzymes (protease and phospholipase) production. Tm25 and Tm26 isolates were able to form moderate to strong biofilm. Study suggested that biofilm formation was promoted due to osmotic oxidative stresses of H2O2, NaCl and at pH 6.3, while antifungal agents caused a reduction in biofilm growth.
Page(s):
81-81
DOI:
DOI not available
Published:
Journal: Abstract Book on Global Science Technology and Management Conference, Volume: 0, Issue: 0, Year: 2023