ABSTRACT
AIMS: The purpose of this study was to demonstrate the usefulness of lectin obtained from Talisia esculenta (TEL) seeds as a tool to recognize and study Microsporum canis. For this purpose, we investigated the antifungal and marker action of this lectin and the relationship of these effects with the presence of carbohydrates on the structure of this fungus. METHODS AND RESULTS: The in vitro antifungal activity of TEL was analysed by broth microdilution assay. In addition, TEL was assessed against the arthroconidia present on hairs obtained from infected dogs and cats. The affinity of fluorescein isothiocyanate (FITC)-labelled TEL for macroconidia and arthroconidia of M. canis was also tested. The effects of TEL on the growth of the M. canis strains began with 0.125 mg ml(-1), and 100% inhibition was obtained with a concentration of 2 mg ml(-1). The addition of carbohydrates, especially N-acetyl-glucosamine and d-mannose, inhibited these antifungal effects. TEL was able to inhibit the growth of arthroconidial chitin-rich forms of M. canis obtained from hairs of infected animals and strains cultured in Sabouraud agar. FITC-labelled TEL efficiently marked macroconidial and arthroconidial forms of M. canis, as shown by fluorescent microscopy. CONCLUSIONS: These results show that the inhibitory effects of TEL on M. canis growth may be related to the interaction of lectin with the carbohydrates present at the micro-organism's surface, mainly D-mannose and N-acetyl-glucosamine. SIGNIFICANCE AND IMPACT OF THE STUDY: Talisia esculenta can be used as an important tool in the biochemical study of M. canis or as a molecule to recognize this dermatophyte in infected tissue.
Subject(s)
Antifungal Agents/pharmacology , Cat Diseases/microbiology , Dermatomycoses/veterinary , Dog Diseases/microbiology , Microsporum/drug effects , Microsporum/isolation & purification , Plant Lectins/pharmacology , Sapindaceae/chemistry , Animals , Biological Assay , Cats , Dermatomycoses/microbiology , Dogs , Hair/microbiology , Microbial Sensitivity Tests , Microsporum/growth & development , Seeds/chemistry , Spores, Fungal/drug effectsABSTRACT
A total of 30 strains of Fusobacterium sp. isolated from gengival sulcus of 28 equines was studied in the period between January/1997 and April/1998. Bacterial isolation and antimicrobial resistance were determined by biochemical analyses and by the disk elution method. The species most frequently isolated was Fusobacterium nucleatum. The following resistance rates were observed: 10 per cent for penicillin G, 87 per cent for eritromycin, and 97 per cent for sulfonamide. Theses results emphasize the need for monitoring the susceptibility patterns of this important bacterial groups frequently isolated from normal sites in equines