Inhibitory effect of farnesol on biofilm formation by Candida tropicalis

Candidiasis associated with indwelling medical devices is especially problematic since they can act as substrates for biofilm growth which are highly resistant to antifungal drugs. Farnesol is a quorum-sensing molecule that inhibits filamentation and biofilm formation in Candida albicans. Since in recent years Candida tropicalis have been reported as an important and common non-albicans Candida species with high drug resistance pattern, the inhibitory effect of farnesol on biofilm formation by Candida tropicalis was evaluated. Five Candida tropicalis strains were treated with different concentration of farnesol [0, 30 and 300 micro M] after 0, 1 and 4 hrs of adherence and then they were maintained under biofilm formation condition in polystyrene, 96-well microtiter plates at 37°C for 48 hrs. Biofilm formation was measured by a semiquantitative colorimetric technique based on reduction assay of 2,3- bis -2H-tetrazolium- 5- carboxanilide [XTT]. The results indicated that the initial adherence time had no effect on biofilm formation and low concentration of farnesol [30 micro M] could not inhibit biofilm formation. However the presence of non-adherent cells increased biofilm formation significantly and the high concentration of farnesol [300 micro M] could inhibit biofilm formation. Results of this study showed that the high concentration of farnesol could inhibit biofilm formation and may be used as an adjuvant in prevention and in therapeutic strategies with antifungal drugs

Actinomyces viscosus isolation from skin lesions in Iran

This paper presents a case-report of cutaneous actinomycosis due to Actinomyces viscosus in a 22 year old man, hospital staff from Tehran with multiple fistulous tracts in his right hand and a history of skin injury due to thorn of plant. Diagnosis was based on the observation of gram positive coccoid, diphtheroid and long branching filaments in direct examination of pus from fistulous tracts and isolation of microorganism in thioglycolate and Brain Heart Infusion [BHI] agar media in anaerobic conditions and some physiologic tests. Treatment of lesion was down with doxycyclin and penicillin 3 months and healing was acquired