In vitro analysis of the antibacterial activity of Oedogonium capillare against pathogenic bacteria in fish

Abstract

THE PRESENT STUDY PROVED IN VITRO THE CAPABILITY OF AN EXTRACT OF OEDOGONIUM CAPILLARE, A FRESH WATER GREEN ALGAE, TO BE AN EFFECTIVE ANTIBACTERIAL AGENT AGAINST 23 DIFFERENT BACTERIAL SPECIES OF ENTEROBACTERIACEAE, PSEUDOMONADACEAE, AEROMONADACEAE AND VIBRIONACEAE FAMILIES, THAT ARE PATHOGENS IN HUMANS AND IMPORTANT IN AQUACULTURE. ALL THE DIFFERENT WILD STRAINS WERE ISOLATED FROM CARASSIUS AURATUS FISH CULTIVATED IN FISH FARMS IN THE STATE OF MORELOS, MEXICO. AFTER BEING PURIFIED THE STRAINS WERE IDENTI- FIED THROUGH THE API-20E AND API-20NE METHODS. THE ALGAE WERE COLLECTED FROM THE PONDS LOCATED IN THE ""CENTER OF BIOLOGICAL AND AQUACULTURE RESEARCHES"" IN XOCHIMILCO, MEXICO. AFTER THE ALGAE HAD BEEN DRIED AND HOMOGENIZED, THEY WERE SUBJECTED TO HEXANE EXTRACTIONS AT REFL UX TEMPERATURE. THE SECOND EXTRACTION WAS MADE USING A CHROMATOGRAPHIC COLUMN OF SILICA GEL AND ETHYL-CHLOROPHORM. IN ORDER TO DETERMINE THE SUSCEPTIBILITY OF BACTERIA TO THE ACTIVITY OF THE EXTRACT A STANDARDIZED DIFFUSION DISK TEST WAS CARRIED OUT. FILTERED PAPER DISKS WERE SATURATED WITH THE EXTRACT OBTAINED FROM THE O. CAPILLARE ALGAE AND COMMERCIAL ANTIBIOTICS WIDELY USED IN THE FISH INDUSTRY SUCH AS: KANAMYCIN, CHLORAMPHENICOL AND TETRACYCLINE. IN ORDER TO DETERMINE THE PRESENCE OR R-PLASMID IN THE STRAINS, THE ALKALINE LYSIS TECHNIQUE, WAS USED. THE WHOLE EXPERIMENT WAS MIRRORED USING STRAINS OF THE AMERICAN TYPE CULTURE COLLECTION. THE ANTIBACTERIAL BEHAVIOR OF O. CAPILLARE WAS COMPARED WITH EACH OF THE AFOREMENTIONED COMMERCIAL ANTIBIOTICS WITH A CORRELATION ANALYSIS. HIGH CORRELATION COEFFICIENTS WERE OBTAINED BETWEEN THE ACTIVITY OF THE ALGAE EXTRACT AND THE ANTIBIOTICS USED IN THIS STUDY. OF THE THREE ANTIBIOTICS STUDIED, KANAMYCIN WAS FOUND TO BE THE MOST RELATED ONE TO THE ANTIBACTERIAL ACTIVITY OF O. CAPILLARE. A HIGHER ANTIBACTERIAL ACTIVITY OF THE EXTRACT WAS FOUND ON THE COLLECTION STRAINS. THE AVERAGE DIAMETER OF THE INHIBITION HALOS IN THE CULTURES OF THE FOUR BACTERIAL FAMILIES OF THIS GROUP WAS GREATER THAN THAT OF THE WILD STRAINS, POSSIBLY DUE TO THE PRESENCE OF R-PLASMIDS IN THE LATTER GROUP.